Patent Publication Number: US-8109805-B2

Title: Toy vehicle, and wheel device and carriage frame for the toy vehicle

Description:
TECHNICAL FIELD 
     The present invention relates to a wheel device for a toy vehicle traveling on a pair of metal rails while attracting with magnets and a toy vehicle including the wheel device. 
     BACKGROUND ART 
     A conventional wheel device for a toy vehicle traveling on a pair of metal rails while attracting with magnets has left and right wheels attracting the rails with magnetic forces (e.g., Patent Document 1). A conventional wheel device for a toy vehicle traveling with a motor provided inside the toy vehicle being rotated by power fed from the pair of rails is structured so that metal wheels provided on opposite sides of an axle come in contact with the pair of rails thereby to receive power feeding (e.g., Patent Document 2).
     Patent Document 1: Japanese Patent Application National Publication No. 60-500361   Patent Document 2: Japanese Patent Application Laid-Open No. 52-90093   

     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     When a conventional toy vehicle is traveling a curve, an inner wheel tries to rotate slowly while an outer wheel tries to rotate fast. However, both the wheels are fixed to an axle and therefore rotate at substantially the same speed. As a result, the inner wheel or the outer wheel may slip on the rail. In the case of the above-described conventional wheel device having both the wheels rotating while attracting with the magnets, both the wheels rotate similarly during straight traveling and therefore do not receive very large resistance of magnetic forces during rotation. During curve traveling, however, one of the wheels slips on the rail as described above and therefore the resistance of the magnetic forces is large, which equates to the state under braking. As a result, the toy vehicle is decelerated, a load on the motor increases, and consumption of electricity increases. 
     The invention of the present application has been accomplished with the above problems in view and it is an object of the invention to provide a wheel device for a toy vehicle which receives, even during curve traveling, as small resistance of magnetic forces as that received during straight traveling to suppress a load applied on a motor by causing one of a pair of wheels rotating on a pair of metal rails to attract with a magnet, and a toy vehicle using the wheel device. 
     Means for Solving the Problem 
     To achieve the above object, in a wheel device for a toy vehicle according to a first aspect of the invention of the present application, 
     (a) the wheel device is adapted to be placed on a pair of rails and includes a first axle and first and second wheels provided on opposite sides of the first axle, 
     (b) the first wheel includes a first wheel main body rolling on one of the rails and a first flange guided by the one rail and the first wheel main body and the first flange are made of a synthetic resin, and 
     (c) the second wheel includes a second wheel main body rolling on the other of the rails and a second flange guided by the other rail and at least the second wheel main body is formed of a member attracting with a magnetic force. 
     To achieve the above object, in a wheel device for a toy vehicle according to a second aspect of the invention of the present application, the second wheel main body is formed of a magnet. 
     To achieve the above object, in a wheel device for a toy vehicle according to a third aspect of the invention of the present application, the second wheel main body is configured by a magnet and a rolling shaft having the magnet therein and formed in the shape of a round shaft. 
     To achieve the above object, in a wheel device for a toy vehicle according to a fourth aspect of the invention of the present application, the rolling shaft is made of ferromagnetic material. 
     To achieve the above object, in a wheel device for a toy vehicle according to a fifth aspect of the invention of the present application, the first wheel main body, the first flange, the first axle, and the second flange are made of a synthetic resin. 
     To achieve the above object, in a wheel device for a toy vehicle according to a sixth aspect of the invention of the present application, the first axle is formed with a gear. 
     To achieve the above object, in a toy vehicle according to a seventh aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) each of the carriage frames is provided with a pair of wheel devices for a toy vehicle according to any one of the first to sixth aspect of the invention, and 
     (c) the pair of wheel devices is rotatably mounted to the carriage frame so that the second wheel main bodies formed of the members attracting with the magnetic forces come in contact with different rails. 
     To achieve the above object, in a wheel device for a toy vehicle according to a eighth aspect of the invention of the present application, 
     (a) the device is adapted to be placed on a pair of rails and includes a second axle and third and fourth wheels provided on opposite sides of the second axle, 
     (b) the third wheel includes a third wheel main body rolling on one of the rails and a third flange guided by the one rail and the third wheel main body and the third flange are made of a synthetic resin, 
     (c) the fourth wheel includes a fourth wheel main body rolling on the other of the rails and a fourth flange guided by the other rail, and 
     (d) the fourth wheel main body includes the second axle and formed of a member attracting with a magnetic force. 
     To achieve the above object, in a wheel device for a toy vehicle according to a ninth aspect of the invention of the present application, the fourth wheel main body is formed of a magnet. 
     To achieve the above object, in a wheel device for a toy vehicle according to a tenth aspect of the invention of the present application, the fourth wheel main body is formed of a magnet and a rolling shaft having the magnet therein and made of ferromagnetic material in the shape of a round shaft. 
     To achieve the above object, in a wheel device for a toy vehicle according to a eleventh aspect of the invention of the present application, the third wheel main body, the third flange, and the fourth flange are made of a synthetic resin. 
     To achieve the above object, in a wheel device for a toy vehicle according to a twelfth aspect of the invention of the present application, the second axle is provided with a conductive ring electrically conductive with the second axle between the third wheel and the fourth wheel. 
     To achieve the above object, in a toy vehicle according to a thirteenth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) each of the carriage frames is provided with a pair of wheel devices for a toy vehicle according to any one of eighth to twelfth aspect of the invention, and 
     (c) the pair of wheel devices is rotatably mounted on the carriage frame so that the fourth wheel main bodies formed of the members attracting with the magnetic forces come in contact with different rails. 
     To achieve the above object, in a toy vehicle according to a fourteenth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) the carriage frame mounted to one of the front and rear portions is provided with a pair of wheel devices for a toy vehicle according to the sixth aspect of the invention, 
     (c) the carriage frame mounted to the other of the front and rear portions is provided with a pair of wheel devices for a toy vehicle according to the twelfth aspect of the invention, 
     (d) the chassis is provided with a drive motor and a gear train for transmitting rotation of the drive motor to the gears of the pair of wheel devices for a toy vehicle according to the sixth aspect of the invention, and 
     (e) the chassis is provided with a first conductive contact coming in sliding contact with one of the conductive rings of the pair of wheel devices for a toy vehicle according to the twelfth aspect of the invention and a second conductive contact coming in sliding contact with the other conductive ring, the first conductive contact being electrically connected to one of a positive terminal and a negative terminal of the drive motor and the second conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the drive motor. 
     To achieve the above object, in a toy vehicle according to a fifteenth aspect of the invention of the present application, the second wheel main bodies of the pair of wheel devices for a toy vehicle according to the sixth aspect of the invention formed of the members attracting with the magnetic forces and the fourth wheel main bodies of the pair of wheel devices for a toy vehicle according to the twelfth aspect of the invention formed of the members attracting with the magnetic forces are arranged so as to alternately come in contact with the different rails. 
     To achieve the above object, in a toy vehicle according to a sixteenth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) the carriage frame mounted to the front or rear portion is provided with a pair of wheel devices for a toy vehicle according to the twelfth aspect of the invention, 
     (c) the chassis is provided with an electric component, and 
     (d) the chassis is provided with a first conductive contact coming in sliding contact with one of the conductive rings of the pair of wheel devices for a toy vehicle according to the twelfth aspect of the invention and a second conductive contact coming in sliding contact with the other conductive ring, the first conductive contact being electrically connected to one of a positive terminal and a negative terminal of the electric component and the second conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the electric component. 
     To achieve the above object, in a toy vehicle according to a seventeenth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) the carriage frames mounted to the front and rear portions are provided with wheel devices for a toy vehicle according to the twelfth aspect of the invention, 
     (c) the chassis is provided with an electric component, and 
     (d) the chassis is provided with a third conductive contact coming in sliding contact with the conductive ring of the wheel device for a toy vehicle according to the twelfth aspect of the invention at the front portion and a fourth conductive contact coming in sliding contact with the conductive ring of the wheel device for a toy vehicle according to the twelfth aspect of the invention at the rear portion, the third conductive contact being electrically connected to one of a positive terminal and a negative terminal of the electric component and the fourth conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the electric component. 
     To achieve the above object, in a wheel device for a toy vehicle according to a eighteenth aspect of the invention of the present application, 
     (a) the device is adapted to be placed on a pair of rails and includes an axle and a pair of wheels provided on opposite sides of the axle and 
     (b) each of the wheels includes a wheel main body having a mounting shaft and a flange, and a magnet ring mounted on the mounting shaft, the magnet ring rolling on the rail and the flange being guided by the rail. 
     To achieve the above object, in a wheel device for a toy vehicle according to a nineteenth aspect of the invention of the present application, the axle is made of a synthetic resin and the wheel main body is made of ferromagnetic material. 
     To achieve the above object, in a wheel device for a toy vehicle according to a twentieth aspect of the invention of the present application, the axle is provided with a gear. 
     To achieve the above object, in a wheel device for a toy vehicle according to a twenty-first aspect of the invention of the present application, of the wheel main body is formed with a support recessed portion in which the axle is rotatably supported. 
     To achieve the above object, in a wheel device for a toy vehicle according to a twenty-second aspect of the invention of the present application, 
     (a) the device is adapted to be placed on a pair of rails and includes a second axle and third and fourth wheels provided on opposite sides of the second axle, 
     (b) the third wheel includes a third wheel main body having a mounting shaft and a third flange, and a magnet ring mounted to the mounting shaft, the magnet ring rolling on one of the rails and the third flange being guided by the one rail, 
     (c) the fourth wheel includes a fourth wheel main body rolling on the other rail and a fourth flange guided by the other rail, 
     (d) the second axle, the third wheel main body, and the fourth wheel are made of ferromagnetic material, 
     (e) the third wheel main body is directly mounted on one side of the second axle to be electrically conductive with the second axle, and 
     (f) the fourth wheel is mounted on the other side of the second axle with an auxiliary member made of a synthetic resin interposed therebetween not to be electrically conductive with the second axle. 
     To achieve the above object, in a wheel device for a toy vehicle according to a twenty-third aspect of the invention of the present application, the wheel main body is formed with a support recessed portion in which the axle is rotatably supported. 
     To achieve the above object, in a toy vehicle according to a twenty-fourth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) the carriage frame mounted to one of the front and rear portions is provided with a pair of wheel devices for a toy vehicle according to the twentieth aspect of the invention, 
     (c) the carriage frame mounted to the other of the front and rear portions is provided with a pair of wheel devices for a toy vehicle according to the twenty second aspect of the invention, 
     (d) the chassis is provided with a drive motor and a gear train for transmitting rotation of the drive motor to the gears of the pair of wheel devices for a toy vehicle according to the twentieth aspect of the invention, and 
     (e) the chassis is provided with a first conductive contact coming in sliding contact with one of the second axles of the pair of wheel devices for a toy vehicle according to the twenty second aspect of the invention and a second conductive contact coming in sliding contact with the other second axle, the first conductive contact being electrically connected to one of a positive terminal and a negative terminal of the drive motor and the second conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the drive motor. 
     To achieve the above object, in a toy vehicle according to a twenty-fifth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) the carriage frame mounted to the front or rear portion is provided with a pair of wheel devices for a toy vehicle according to the twenty-second aspect of the invention, 
     (c) the chassis is provided with an electric component, and 
     (d) the chassis is provided with a third conductive contact coming in sliding contact with one of the second axles of the pair of wheel devices for a toy vehicle according to the twenty-second aspect of the invention and a fourth conductive contact coming in sliding contact with the other second axle, the third conductive contact being electrically connected to one of a positive terminal and a negative terminal of the electric component and the fourth conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the electric component. 
     To achieve the above object, in a toy vehicle according to a twenty-sixth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and carriage frames mounted to a front and a rear of the chassis, 
     (b) the carriage frames mounted to the front and rear portions are respectively provided with wheel devices for a toy vehicle according to the twenty-second aspect of the invention, 
     (c) the chassis is provided with an electric component, and 
     (d) the chassis is provided with a third conductive contact coming in sliding contact with the second axle of the wheel device for a toy vehicle according to the twenty-second aspect of the invention mounted to the front carriage frame and a fourth conductive contact coming in sliding contact with the second axle of the wheel device for a toy vehicle according to the twenty-second aspect of the invention mounted to the rear carriage frame, the third conductive contact being electrically connected to one of a positive terminal and a negative terminal of the electric component and the fourth conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the electric component. 
     To achieve the above object, in a carriage frame for a toy vehicle according to a twenty-seventh aspect of the invention of the present application, 
     (a) the carriage frame includes a main frame and a pair of bearing plates mounted to the main frame so that the plates face each other, 
     (b) the bearing plate is made of ferromagnetic material and provided with a pair of support protruding portions and a protruding chip, and 
     (c) the support recessed portions of the wheel device for a toy vehicle according to the twenty-first aspect of the invention are rotatably supported on the opposed support protruding portions of the pair of bearing plates. 
     To achieve the above object, in a carriage frame for a toy vehicle according to a twenty-eighth aspect of the invention of the present application, 
     (a) the carriage frame includes a main frame and a pair of bearing plates mounted to the main frame so that the plates face each other, 
     (b) the bearing plate is made of ferromagnetic material and provided with a pair of support protruding portions and a protruding chip, and 
     (c) the support recessed portions of the wheel device for a toy vehicle according to the twenty-third aspect of the invention are rotatably supported on the opposed support protruding portions of the pair of bearing plates. 
     To achieve the above object, in a toy vehicle according to a twenty-ninth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and the carriage frame for a toy vehicle according to the twenty-seventh aspect of the invention mounted to a front portion or a rear portion of the chassis, 
     (b) the chassis is provided with a drive motor and a gear train for transmitting rotation of the drive motor to the gears of the pair of wheel devices for a toy vehicle according to the twenty-second aspect of the invention, and 
     (c) the chassis is provided with a first conductive contact coming in contact with one of the protruding chips of the carriage frame for a toy vehicle according to the twenty-seventh aspect of the invention and a second conductive contact coming in contact with the other protruding chip of the carriage frame for a toy vehicle according to the twenty-seventh aspect of the invention, the first conductive contact being electrically connected to one of a positive terminal and a negative terminal of the drive motor and the second conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the drive motor. 
     To achieve the above object, in a toy vehicle according to thirtieth aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and the carriage frame for a toy vehicle according to the twenty-seventh aspect of the invention mounted to a front portion or a rear portion of the chassis, 
     (b) the chassis is provided with an electric component, and 
     (c) the chassis is provided with a third conductive contact coming in contact with one of the protruding chips of the carriage frame for a toy vehicle according to the twenty-seventh aspect of the invention and a fourth conductive contact coming in contact with the other protruding chip of the carriage frame for a toy vehicle according to the twenty-seventh aspect of the invention, the third conductive contact being electrically connected to one of a positive terminal and a negative terminal of the electric component and the fourth conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the electric component. 
     To achieve the above object, in a carriage frame for a toy vehicle according to a thirty-first aspect of the invention of the present application, 
     (a) the carriage frame includes a main frame and a pair of bearing plates mounted to the main frame so that the plates face each other, 
     (b) each of the bearing plates is made of ferromagnetic material and provided with a pair of support protruding portions and a protruding chip, 
     (c) the wheel device is rotatably supported on the opposed support protruding portions of the pair of bearing plates, 
     (d) the wheel device is adapted to be placed on a pair of rails and includes an axle and a pair of wheels provided on opposite sides of the axle, 
     (e) the wheels includes a wheel main body rolling on the rail and a flange guided by the rail, 
     (f) the axle is made of a synthetic resin and the wheels are made of ferromagnetic material, and 
     (g) the wheel main body is formed with a support recessed portion to be rotatably supported on the support protruding portion of the bearing plate. 
     To achieve the above object, in a toy vehicle according to the thirty-second aspect of the invention of the present application, 
     (a) a toy vehicle main body includes a chassis and the carriage frame for a toy vehicle according to the thirty-first aspect of the invention mounted to a front portion or a rear portion of the chassis, 
     (b) the chassis is provided with an electric component, and 
     (c) the chassis is provided with a third conductive contact coming in contact with one of the protruding chips of the carriage frame for a toy vehicle according to the thirty-first aspect of the invention and a fourth conductive contact coming in contact with the other protruding chip of the carriage frame for a toy vehicle according to the thirty-first aspect of the invention, the third conductive contact being electrically connected to one of a positive terminal and a negative terminal of the electric component and the fourth conductive contact being electrically connected to the other of the positive terminal and the negative terminal of the electric component. 
     Effects of the Invention 
     In the wheel device according to the present invention, one of the pair of wheels rolling on the pair of metal rails attracts with a magnetic force. As a result, the device receives, even during curve traveling, as small resistance of the magnetic force as that received during straight traveling and a load applied on a motor can be suppressed. 
     In the toy vehicle according to the present invention, the wheel main bodies of the wheel devices having the above effect and formed of the members attracting with the magnetic forces alternately come in contact with different rails. As a result, the toy vehicle can travel while keeping good balance thereof. 
    
    
     BEST MODES FOR CARRYING OUT THE INVENTION 
     An embodiment of a wheel device for a toy vehicle and a toy vehicle mounted with the wheel device according to the invention of the present application will be described based on  FIGS. 1 to 9 .  FIGS. 1(   a ) to  1 ( c ) are general views of the embodiments of a drive wheel device for a toy vehicle according to the present invention, wherein  FIG. 1(   a ) is a front view,  FIG. 1(   b ) is a sectional view, and  FIG. 1(   c ) is another front sectional view.  FIGS. 2(   a ) and  2 ( b ) are exploded perspective views of the drive wheel devices for a toy vehicle according to the present invention mounted into a carriage, wherein  FIG. 2(   a ) is a perspective view from below and  FIG. 2(   b ) is a perspective view from above.  FIG. 3  is an exploded perspective view of the drive wheel devices and follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 4(   a ) and  4 ( b ) are sectional views of the wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle, wherein  FIG. 4(   a ) is a sectional view of an essential part when the drive wheel devices are mounted and  FIG. 4(   b ) is a sectional view of an essential part when the follower wheel devices are mounted.  FIGS. 5(   a ) and  5 ( b ) are assembly drawings of  FIG. 4 , wherein  FIG. 5(   a ) is a perspective view from above and  FIG. 5(   b ) is a perspective view from below.  FIG. 6  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 7(   a ) and  7 ( b ) are assembly drawings of  FIG. 6 , wherein  FIG. 7(   a ) is a perspective view from above and  FIG. 7(   b ) is a perspective view from below.  FIG. 8  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 9(   a ) and  9 ( b ) are assembly drawings of  FIG. 8 , wherein  FIG. 9(   a ) is a perspective view from above and  FIG. 9(   b ) is a perspective view from below. 
     As shown in  FIGS. 1(   a ) to  1 ( c ), the wheel device  1 ,  1 A for a toy vehicle is adapted to be placed on a pair of rails  261  and formed of a first axle  2 , and a first wheel  10  and a second wheel  20  provided on opposite sides of the first axle  2 . The first wheel  10  includes a first wheel main body  11  rolling on one of the rails  261  and a first flange  12  guided by the one rail and the first wheel main body  11  and the first flange  12  are made of a synthetic resin. The second wheel  20  includes a second wheel main body  21  rolling on the other of the rails  261  and a second flange  22  guided by the other rail  261  and at least the second wheel main body  21  is formed of a magnet. 
     The wheel device  1 ,  1 A for a toy vehicle may be formed by integrally molding the first wheel main body  11 , the first flange  12 , the first axle  2 , and the second flange  22  of a synthetic resin. The first axle  2  of the wheel device  1 ,  1 A for a toy vehicle may be formed with a gear  8 . 
     As shown in  FIG. 3 , a toy vehicle main body  102  of the toy vehicle  101  has a chassis  103  and carriage frames  71 ,  71  mounted to a front and a rear of the chassis  103 . The carriage frame  71  is provided with a pair of wheel devices  1 ,  1 A for a toy vehicle. The pair of wheel devices  1 ,  1 A is rotatably mounted to the carriage frame  71  so that the second wheel main bodies  21  formed of the magnets are in contact with different rails  261 . 
     As shown in  FIGS. 3 to 4(   b ), a wheel device  31  for a toy vehicle is adapted to be placed on the pair of rails  261  and formed of a second axle  32 , and a third wheel  40  and a fourth wheel  50  provided on opposite sides of the second axle  32 . The third wheel  40  includes a third wheel main body  41  rolling on one of the rails  261  and a third flange  42  guided by the one rail  261  and the third wheel main body  41  and the third flange are made of a synthetic resin. 
     The fourth wheel  50  includes a fourth wheel main body  51  rolling on the other of the rails  261  and a fourth flange  52  guided by the other rail  261 . The fourth wheel main body  51  is formed of a magnet, the fourth flange  52  is made of a synthetic resin, and the fourth wheel main body  51  is attached to the fourth flange  52 . The second axle  32  is formed of the same member as the fourth wheel main body  51 . In the wheel device  31  for a toy vehicle, the second axle  32  may be provided with a conductive ring  60  interposed between the third flange  42  and the fourth flange  52 . 
     As shown in  FIG. 3 , the toy vehicle main body  102  of the toy vehicle  101  has the chassis  103  and the carriage frames  71 ,  71  mounted to the front and rear of the chassis  103 . Each of the carriage frames  71 ,  71  is provided with a pair of wheel devices  31  for a toy vehicle. The pair of wheel devices  31 ,  31  are rotatably mounted to the carriage frame  71  so that the fourth wheel main bodies  51  formed of the magnets come in contact with different rails  261 . 
     As shown in  FIG. 3 , the toy vehicle main body  102  of the toy vehicle  101  has the chassis  103  and the carriage frames  71 ,  71  mounted to the front and rear of the chassis  103 . The carriage frame  71  mounted to one of the front and rear portions is provided with a pair of wheel devices  1  for a toy vehicle. The carriage frame  71  mounted to the other of the front and rear portions is provided with a pair of wheel devices  31  for a toy vehicle. The chassis  103  is provided with a drive motor  116  and a gear train  120  for transmitting rotation of the drive motor  116  to the gears  8 ,  8  of the pair of wheel devices  1 ,  1  for a toy vehicle. The chassis  103  is provided with a first conductive contact  141  which is in sliding contact with one of the conductive rings  60  of the pair of wheel devices  31 ,  31  for a toy vehicle and a second conductive contact  145  which is in sliding contact with the other conductive ring  60 . The first conductive contact  141  is electrically connected to one of a positive terminal and a negative terminal of the drive motor  116  and the second conductive contact  145  is electrically connected to the other of the positive terminal and the negative terminal of the drive motor  116 . 
     As shown in  FIG. 16 , in the toy vehicle  101 , the second wheel main bodies  21  of the pair of wheel devices  1  for a toy vehicle and formed of the magnets and the magnet fourth wheel main bodies  51  of the pair of wheel devices  31  for a toy vehicle and formed of the magnets are arranged to alternately come in contact with different rails  261 . 
     The drive wheel device, the follower wheel device, and the toy vehicle mounted with them will be described further in detail. As shown in  FIGS. 1(   a ) to  2 , the drive wheel device  1  includes the first axle  2 , the first wheel  10 , and the second wheel  20 . The first axle  2  is made of a synthetic resin and formed into a cylindrical shape. One side face  3  of the first axle  2  is formed with a first round shaft recessed portion  5  coaxial with the first axle  2 . The other side face  6  of the first axle  2  is formed with a second round shaft recessed portion  7  coaxial with the first axle  2  and having a larger diameter than the first round shaft recessed portion  5 . A peripheral face of the first axle  2  is integrally molded with the gear  8 . Cog tips of the gear  8  are curved to form spherical surfaces. 
     The first wheel  10  includes the first wheel main body  11 , the first flange  12 , and a fitting shaft  13  and is integrally molded of a synthetic resin. An outer side face  15  of the first flange  12  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. The outer side face  15  of the first flange  12  is provided with the first wheel main body  11  substantially coaxial with the first flange  12 . An inner side face  16  of the first flange  12  is provided with the fitting shaft  13  substantially coaxial with the first flange  12 . The first wheel  10  is fitted and fixed into the first round shaft recessed portion  5  of the first axle  2 . 
     The second wheel  20  includes the second wheel main body  21 , the second flange  22 , and a boss portion  23 . The second wheel main body  21  is in the shape of a round shaft having substantially the same outer diameter as the first wheel main body  11  and is formed of the magnet, e.g., a neodymium magnet. An outer side face  25  of the second flange  22  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. An inner side face  26  of the second flange  22  is provided with the boss portion  23  substantially coaxial with the second flange  22  and having substantially the same outer diameter as the first axle  2 . The second flange  22  and the boss portion  23  are integrally molded of a synthetic resin. 
     The second flange  22  and the boss portion  23  are formed, substantially at centers thereof, with a through hole  27  having substantially the same inner diameter as the second round shaft recessed portion  7  of the first axle  2 . The second wheel main body  21  passes through the through hole  27  and is fixed with its opposite sides protruding from the second flange  22  and the boss portion  23 . The second wheel  20  is fixed with a protruding portion  29  of the second wheel main body  21  protruding from the boss portion  23  side being fitted in the second round shaft recessed portion  7  of the first axle  2 . The gear  8  is in a substantially middle position between the first flange  12  and the second flange  22 . 
     As described above, the drive wheel device  1  is made of a synthetic resin excluding the second wheel main body  21  that is formed of the magnet. Therefore, as shown in  FIG. 1(   c ), the drive wheel device  1 A may be formed by integrally molding the first wheel  10 , the first axle  2 , the boss portion  23 , and the second flange  22  with a synthetic resin and arranging the second wheel main body  21  so that it protrudes from the second flange  22 . 
     As shown in  FIGS. 3 and 4(   b ), the follower wheel device  31  includes the second axle  32 , the third wheel  40 , the fourth wheel  50 , and the conductive rings  60 . The second axle  32  is in the shape of a round shaft having substantially the same outer diameter as the first wheel main body  11  and is formed of the magnet, for example, a neodymium magnet. The third wheel  40  includes the third wheel main body  41 , the third flange  42 , and a boss portion  43  and is integrally molded of a synthetic resin. An outer side face  45  of the third flange  42  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. The outer side face  45  of the third flange  42  is provided with the third wheel main body  41  substantially coaxial with the third flange  42 . An inner side face  46  of the third flange  42  is provided with the boss portion  43  substantially coaxial with the third flange  42 . The boss portion  43  is formed substantially at a center thereof with a fitting hole  47  in which one end of the second axle  32  is to be fitted. The second axle  32  is formed of the neodymium magnet, has substantially the same outer diameter as the third wheel main body  41 , and is substantially coaxial with the third wheel main body  41 . 
     The fourth wheel  50  includes the fourth flange  52  and a boss portion  53  and is integrally molded of a synthetic resin. An outer side face  55  of the fourth flange  52  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. An inner side face  56  of the fourth flange  52  is provided with the boss portion  53  substantially coaxial with the fourth flange  52 . The fourth flange  52  and the boss portion  53  are formed, substantially at centers thereof, with a through hole  57  having substantially the same inner diameter as the fitting hole  47  of the third wheel  40 . The second axle  32  passes through the through hole  57  and is fixed with its opposite sides protruding from the fourth flange  52  and the boss portion  53 . A protruding portion  39  of the second axle  32  protruding from the fourth flange  52  side forms the fourth wheel main body  51  of the fourth wheel  50 . In other words, the fourth wheel main body  51  forms the second axle  32 . 
     The second axle  32  (fourth wheel main body  51 ) is mounted with the conductive ring  60 , which is interposed between the third flange  42  and the fourth flange  52 . The conductive ring  60  may be made of any kind of material if it is conductive material. In the embodiment, the conductive ring  60  is made of phosphor bronze. Although the conductive ring  60  is fixedly mounted to the second axle  32  (fourth wheel main body  51 ), it may be rotatably mounted. Although the fourth wheel main body  51  and the second axle  32  are made of the same material in the embodiment, the fourth wheel main body  51  may be made of a first conductive material with a magnetic property, the second axle  32  may be made of second conductive material having a different outer diameter from the fourth wheel main body  51 , and the fourth wheel main body  51  and the second axle  32  may be provided to be adjacent to each other. 
     As shown in  FIG. 6 , a follower wheel device  65  includes an axle  66  and a pair of wheels  67  and is integrally molded of a synthetic resin. Each of the wheels  67  includes a wheel main body  68  and a flange  69 . The above-described drive wheel devices  1  and the follower wheel devices  31 ,  65  are rotatably mounted to the carriage frames  71  of the toy vehicle  101  as shown in  FIGS. 3 ,  6 . The drive wheel devices  1  and the follower wheel devices  31 ,  65  are mounted into the carriage frames  71  thereby to form carriages  70 . 
     As shown in  FIGS. 2(   a ) and  2 ( b ), the carriage frame  71  includes a substantially rectangular main frame  72 , a middle member  73  for partitioning an inside of the main frame  72 , and substantially U-shaped bearing members  75 , and so forth, and is integrally molded of a synthetic resin. The main frame  72  includes a pair of longitudinal members  76 ,  76  in a longitudinal direction and a pair of lateral members  77 ,  77  in a lateral direction and provided at opposite ends of the longitudinal members  76 ,  76 . An outer face  78  of the lateral member  77  is formed of a convex curved face in the shape of an arc having a center substantially at a center of the main frame  72 . 
     The middle member  73  is installed to connect substantially central portions of the pair of longitudinal members  76 ,  76  and in positions lower than the lateral members  77 ,  77 . As described above, the middle member  73  forms housing portions  81 ,  82  for housing the wheel devices  1 ,  31 ,  65  in the main frame  72 . Each of the housing portions  81 ,  82  is provided with the pair of substantially U-shaped bearing members  75 ,  75 . The bearing members  75  are provided to be adjacent to an inner face  79  of the lateral member  77  and an inner side face  74  of the middle member  73 . The bearing members  75 ,  75  bear the first axle  2  and the boss portion  23  of the drive wheel device  1 , the boss portions  43 ,  53  of the follower wheel device  31 , and the axle  66  of the follower wheel device  65  so as to be rotatable. 
     Each of the inner faces  79 ,  79  of the lateral members  77 ,  77  of the main frame  72  is formed of guide grooves  85 ,  85  on opposite sides of the pair of bearing members  75 ,  75 . In the guide grooves  85 ,  85 ,  85 ,  85 , a shaft retaining member  90  is detachably mounted as shown in  FIG. 3 . The shaft retaining member  90  is formed in a substantially H shape, formed with guide protrusions  91 ,  91 ,  91 ,  91  to be guided by the guide grooves  85 ,  85 ,  85 ,  85 , and formed, at its lower portion, with shaft retaining protrusions  92 ,  92 ,  92 ,  92 . As shown in  FIG. 4(   a ), the shaft retaining protrusions  92  retain the third wheel main body  41  and the fourth wheel main body  51  of the follower wheel device  31  and the wheel main bodies  68 ,  68  of the follower wheel device  65  from above to position the follower wheel devices  31 ,  65  and to prevent them from coming off the carriage frames  71 . 
     As shown in  FIG. 3 , the toy vehicle main body  102  of the powered toy vehicle  101  includes the chassis  103  and a vehicle body  105  mounted to the chassis  103 . Formed at each of a front portion and a rear portion of a lower face  106  of the chassis  103  is a pair of substantially L-shaped locking members  110 ,  110  which are facing each other and to which the carriage frame  71  can be mounted. Each of the locking members  110  is formed of a sliding contact face  111  coming in sliding contact with the outer face  78  of the lateral member  77  of the carriage frame  71  and an engaging protruding portion  113  to be engaged with a lower face  77   a  of the lateral member  77 . The sliding contact face  111  is formed of a concave curved face in the shape of an arc having substantially the same curvature as the outer face  78  of the lateral member  77 . 
     As shown in  FIG. 3 , a pair of drive wheel devices  1 ,  1  is rotatably mounted onto the bearing members  75  and the like of the carriage frame  71  so that the second wheel main bodies  21  are in opposite positions (coming in contact with different rails) thereby to form the carriage  70 A on the side of the drive. As shown in  FIGS. 5(   a ) and  5 ( b ), if the carriage  70 A on the side of the drive is positioned and rotated between the locking members  110 ,  110  of the chassis  103 , the outer faces  78  of the lateral members  77  of the carriage frame  71  come in sliding contact with the sliding contact faces  111 ,  111  of the pair of locking members  110 ,  110 , the lower faces  77   a  of the lateral members  77  are engaged with the engaging protruding portions  113 ,  113  of the pair of locking members  110 ,  110 , and the carriage  70 A is mounted onto the chassis  103  so as to be rotatable. 
     As shown in  FIG. 3 , a pair of follower wheel devices  31 ,  31  is rotatably mounted to the bearing members  75  and the like of the carriage frame  71  so that the fourth wheel main bodies  51  are in opposite positions (coming in contact with different rails) and the above-described shaft retaining member  90  is mounted to the carriage frame  71  thereby to form the follower-side carriage  70 B. As shown in  FIGS. 5(   a ) and  5 ( b ), the follower-side carriage  70 B is mounted as well similarly to the carriage  70 A. 
     The chassis  103  is mounted with the drive motor  116  and the gear train  120  for transmitting rotation of the drive motor  116  to the gears  8 ,  8  of the pair of drive wheel devices  1 ,  1 . The gear train  120  consists of a drive gear  121  mounted to a drive shaft of the drive motor  116 , a crown gear  122  engaged with the drive gear  121 , a small gear  123  integral with the crown gear  122 , a large gear  125  engaged with the small gear  123 , a small gear  126  integral with the large gear  125 , a large gear  127  engaged with the small gear  126 , a small gear  128  integral with the large gear  127 , a large gear  129  engaged with the small gear  128 , a small gear integral with the large gear  129 , and a final gear  130  integral with the small gear. Cog tips of the final gear  130  are curved into spherical surfaces. 
     The chassis  103  is mounted with a gear box  131  in which the crown gear  122 , the small gear  123 , the large gear  125 , the small gear  126 , the large gear  127 , the small gear  128 , the large gear  129 , the small gear integral with the large gear  129 , and the final gear  130  are rotatably mounted. The final gear  130  is adapted to be placed above the pair of gears  8 ,  8  of the carriage  70 A mounted onto the chassis  103 . The chassis  103  is formed with an opening  133  for allowing the final gear  130  to protrude from the lower face of the chassis  103 , and the final gear  130  protruding from the opening  133  is engaged with the gears  8 ,  8  of the drive wheel devices  1 ,  1  mounted onto the carriage  70 A. 
     The chassis  103  is provided with the conductive contacts  141 ,  145  positioned above the follower wheel devices  31 ,  31  of the carriage  70 B. Each of the conductive contacts  141 ,  145  is a conductive metal sheet and formed with opposite of which being formed with guide chips  142 ,  142  and a spring receiving protruding chip  143  is formed to protrude from an upper portion of each of the conductive contacts  141 ,  145 . In the embodiment, the conductive contacts  141 ,  145  are made of phosphor bronze. The conductive contacts  141 ,  145  are mounted onto cylindrical guide members  151  formed on an upper portion of the chassis  103  not to be rotatable and to be movable in a vertical direction. In other words, each of the guide members  151  is formed, at opposite sides thereof, with guide grooves  152 ,  152  for guiding the guide chips  142 ,  142  of each of the conductive contacts  141 ,  145 . 
     A lower portion of a spring  155  is mounted to the spring receiving protruding chip  143  of each of the conductive contacts  141 ,  145 . The spring  155  is made of conductive metal and an upper end of the spring  155  is retained by a spring retaining chip  156 . The spring retaining chip  156  is formed of a conductive metal sheet, with opposite sides of the spring retaining chip  167  being formed with guide protrusions  157 ,  157 , and is disposed in the guide member  151  while the guide protrusions  157 ,  157  are guided by the guide grooves  152 ,  152  of the guide member  151 . 
     As shown in  FIG. 4(   b ), protrusions  159  for retaining the spring retaining chips  156  are formed to protrude inside the vehicle body  105  when the vehicle body  105  is mounted to the chassis  103 . The chassis  103  is formed with openings  158  for allowing the conductive contacts  141 ,  145  to protrude from the lower face of the chassis  103 . Lower ends of the conductive contacts  141 ,  145  biased downward with resilience of the springs  155  and protruding from the openings  158  come in sliding contact with the conductive rings  60 ,  60  of the follower wheel devices  31 ,  31  mounted to the carriage  70 B. One of the spring retaining chips  156 ,  156  is electrically connected to the positive terminal of the drive motor  116  through an electric cord and the other of the spring retaining chips  156 ,  156  is electrically connected to the negative terminal of the drive motor  116 . 
     As shown in  FIGS. 6 and 7 , a toy vehicle main body  162  of a toy passenger vehicle  161  includes a chassis  163  and a vehicle body  165  mounted to the chassis  163 . Formed at each of a front portion and a rear portion of a lower face  166  of the chassis  163  is a pair of substantially L-shaped locking members  110 ,  110  which are facing each other and to which the carriage frames  71  can be mounted. 
     As shown in  FIG. 6 , the follower wheel devices  31 ,  65  are rotatably mounted to the bearing members  75  . . . of the carriage frame  71  and the above-described shaft retaining member  90  is mounted to the carriage frame  71  thereby to form the follower-side carriage  70 C. As shown in  FIG. 7 , if the follower-side carriage  70 C is positioned and rotated between the locking members  110 ,  110  of the chassis  103 , the outer faces  78  of the lateral members  77  of the carriage frame  71  come in sliding contact with the sliding contact faces  111 ,  111  of the pair of locking members  110 ,  110 , the lower faces  77   a  of the lateral members  77  are engaged with the engaging protruding portions  113 ,  113  of the pair of locking members  110 ,  110 , and the carriage  70 C is rotatably mounted onto the chassis  103 . The follower wheel devices  31 ,  31  of the pair of carriages  70 C,  70 C are rotatably mounted to the bearing members  75 , and the like, of the carriage frames  71  so that the fourth wheel main bodies  51  are in opposite positions (coming in contact with different rails) 
     The chassis  163  is provided with the conductive contacts  141 ,  145  positioned above the follower wheel devices  31  of the carriages  70 C. The conductive contacts  141 ,  145  are mounted to cylindrical guide members  151  formed on an upper portion of the chassis  163  not to be rotatable and to be movable in a vertical direction. A spring receiving protruding chip  143  of each of the conductive contacts  141 ,  145  is mounted with a lower portion of a spring  155 . An upper end of the spring  155  is retained by a spring retaining chip  156 . 
     As shown in  FIG. 4(   b ), there are formed so as to protrude inside the vehicle body  165 , protrusions  167  for retaining the spring retaining chips  156  when the vehicle body  165  is mounted to the chassis  163 . The chassis  163  is formed with openings  168  for allowing the conductive contacts  141 ,  145  to protrude from the lower face of the chassis  163 . Lower ends of the conductive contacts  141 ,  145  biased downward with resilience of the springs  155  and protruding from the openings  168  come in sliding contact with the conductive rings  60 ,  60  of the follower wheel devices  31 ,  31  mounted to the carriages  70 C. Between one and the other of the spring retaining chips  156 , an electric component, for instance, a light emitting device such as an LED, and a sound generating device, is connected electrically. 
     As shown in  FIGS. 8 and 9 , a toy passenger vehicle  171  has basically the same structure as the toy passenger vehicle  161 , but the conductive contacts  141 ,  145  coming in sliding contact with the conductive rings  30  of the follower wheel devices  31  are not provided, because there is no electric component, in the a toy vehicle main body  172 , actuated by power fed from the rails. 
     Next, a rail track device according to the present invention will be described based on  FIGS. 10 to 16 .  FIG. 10  is a perspective view of an embodiment of the rail track device according to the present invention.  FIG. 11  is an exploded perspective view of  FIG. 10 .  FIGS. 12(   a ) to  12 ( d ) are explanatory views of the rail track device, wherein  FIG. 12(   a ) is a plan view,  FIG. 12(   b ) is a sectional view,  FIG. 12(   c ) is a side view, and  FIG. 12(   d ) is a bottom view.  FIGS. 13(   a ) to  13 ( c ) are explanatory views of the rail track device in which a state where a bottom plate is detached from the rail track device is viewed from below.  FIGS. 14(   a ) and  14 ( b ) are explanatory view illustrating a relationship between a rail track belt and metal rails.  FIGS. 15(   a ) to  15 ( e ) are explanatory views showing a method of coupling the rail track devices.  FIG. 16  is a plan view showing a relationship between the metal rails and the wheel devices. 
     As shown in  FIGS. 10 and 11 , the rail track device  201  includes a rail track belt  202  made of a synthetic resin and a pair of metal rails  261 ,  261  to be inserted into a pair of grooves  215 ,  216  formed in the rail track belt  202 . Each of the metal rails  261  is formed with an insertion recessed portion  272  at one end and an insertion protruding portion  281  at the other end. The rail track belt  202  is formed, at one sides of ends thereof, with mounting portions  230 ,  231  to which magnets  250  having conductivity are mounted. The magnets  250  mounted to the mounting portions  230 ,  231  are provided in such positions as to be inside the insertion recessed portions  272  of the metal rails  261  and to be in contact with the metal rails  261 . The rail track belt  202  is coupled to the other rail track belt  202  in such a way that, when an insertion protruding portion  281  of the metal rail  261  of the other rail track belt  202  is inserted into the insertion recessed portion  272  of the metal rail  261 , the magnet  250  attracts the insertion protruding portion  281  of the other metal rail  261  thereby to connect the metal rail  261  to the other metal rail  261 . 
     As shown in  FIGS. 11 ,  14 ( a ), and  14 ( b ), a method of manufacturing the rail track device  201  includes a first step of inserting the pair of metal rails  261  into the pair of grooves  215 ,  216  in the rail track belt  202  made of a synthetic resin, a second step of folding locking lugs  275 ,  278 ,  279 , and  282  of the metal rails  261  to fix the metal rails  261  to the rail track belt  202 , a third step of mounting the magnets  250  to the mounting portions  230 ,  231  formed at the one sides of the ends of the rail track belt  202 , and a fourth step of mounting the bottom plate  245  to a bottom portion of the rail track belt  202 . 
     The rail track device  201  includes the rail track belt  202  made of a synthetic resin and the pair of metal rails  261 ,  261 . The rail track belt  202  includes an upper face plate  203 , a right slope plate  205  provided to be adjacent to a right side of the upper face plate  203 , a left slope plate  206  provided to be adjacent to a left side of the upper face plate  203 , a right side plate  207  provided to be adjacent to a lower end of the right slope plate  205 , a left side plate  208  provided to be adjacent to a lower end of the left slope plate  206 , a front face plate  210  provided to be adjacent to a front end of the upper face plate  203 , and a rear face plate  211  provided to be adjacent to a rear end of the upper face plate  203 . The rail track belt  202  is formed to be hollow and in a trapezoidal shape when viewed from the front. 
     The upper face plate  203  of the rail track belt  202  is formed with protrusions  213  each in the shape of a cross tie. The upper face plate  203  is formed with the pair of grooves  215 ,  216  into which the pair of metal rails  261 ,  261  are inserted. Each of the grooves  215 ,  216  is formed being surrounded by side faces  218 ,  218  and a bottom face  219  into a substantially angular U shape. As shown in  FIG. 14(   b ), the bottom faces  219  are formed, at predetermined portions thereof, with insertion holes  221 ,  222 ,  223 ,  224 . The right groove  215  is formed with the insertion holes  221 ,  222 ,  223 ,  224  in this order from the front face plate  210  side and the left groove  216  is formed with the insertion holes  221 ,  222 ,  223 ,  224  in this order from the rear face plate  211  side. 
     As shown in  FIG. 14(   b ), a back face  226  of the upper face plate  203  is formed with a pair of substantially rectangular magnet housing frames  230 ,  231 . The right magnet housing frame  230  is formed along the right side plate  207  and the front face plate  210  and the left magnet housing frame  231  is formed along the left side plate  208  and the rear face plate  211 . The magnet housing frame  230  is formed with insertion grooves  232 ,  233  into which the metal rail  261  is to be inserted. The magnet housing frame  231  is formed with insertion grooves  235 ,  236  into which the metal rail  261  is to be inserted. The magnet  250  is pushed mounted into each of the magnet housing frames  230 ,  231 . The magnets  250  are formed of a material having conductivity such as neodymium magnets. As shown in  FIG. 13(   c ), formed at predetermined positions of the back face  226  of the upper face plate  203  are bosses  240  each formed with an internal thread portion  241  and bosses  243  each formed with a positioning hole  242 . 
     As shown in  FIG. 11 , the rail track belt  202  has the bottom plate  245  mounted to a hollow chamber surrounded with the front face plate  210 , the rear face plate  211 , the right side plate  207 , and the left side plate  208 . The bottom plate  245  is formed with fitting pins  246  to be fitted in the positioning holes  242  of the upper face plate  203  and through holes  247  facing the internal thread portions  241  of the upper face plate  203 . The bottom plate  245  is mounted to the rail track belt  202  by fitting the fitting pins  246  in the positioning holes  242  of the upper face plate  203  and screwing screws  248  into the internal thread portions  241 . The magnets  250  mounted to the magnet housing frames  230 ,  231  are prevented by the bottom plate  245  from coming off the magnet housing frames  230 ,  231 . 
     Each of the metal rails  261  is formed to have substantially the same length as the rail track belt  202 , has contact faces  262  to come in contact with the bottom face  219  of the groove  215  or  216 , and is formed with a front insertion chip  263  to be inserted into the insertion hole  221  and the insertion grooves  232 ,  233  of the groove  215  or  216 , a first middle insertion chip  265  to be inserted through the insertion hole  222  of the groove  215  or  216 , a second middle insertion chip  266  to be inserted through the insertion hole  223  of the groove  215  or  216 , and a rear insertion chip  267  to be inserted through the insertion hole  224  of the groove  215  or  216 . 
     The front insertion chip  263  is formed with a contact chip  271  to come in contact with the bottom plate  245  and the insertion recessed portion  272 . The magnets  250  mounted to the magnet housing frames  230 ,  231  are housed in the insertion recessed portions  272  and in contact with the insertion chips  263 . The first middle insertion chip  265  is formed with a contact chip  273  to come in contact with the bottom plate  245  and the locking lug  275  to be folded and locked to the back face  226  of the upper face plate  203 . The second middle insertion chip  266  is formed with a contact chip  276  to come in contact with the bottom plate  245  and the locking lugs  278 ,  279  to be folded and locked to the back face  226  of the upper face plate  203 . The rear insertion chip  267  is formed with a contact chip  280  to come in contact with the bottom plate  245 , the insertion protruding portion  281  capable of being inserted into the insertion recessed portion  272  of the front insertion chip  263 , and the locking lug  282  to be folded and locked to the back face  226  of the upper face plate  203 . 
     The pair of metal rails  261  is pushed into the grooves  215 ,  216  of the rail track belt  202 , the rails  261  in opposite orientations to each other. The contact faces  262  come in contact with the bottom face  219 , the front insertion chips  263  are inserted into the insertion holes  221  and the insertion grooves  232 ,  233  of the grooves  215 ,  216 , the first middle insertion chips  265  are inserted through the insertion holes  222  of the grooves  215 ,  216 , the second middle insertion chips  266  are inserted through the insertion holes  223  of the grooves  215 ,  216 , and the rear insertion chips  267  are inserted through the insertion holes  224  of the grooves  215 ,  216 . The locking lugs  275  of the first middle insertion chips  265  are folded and locked to the back face  226  of the upper face plate  203 , the locking lugs  278 ,  279  of the second middle insertion chips  266  are folded and locked to the back face  226  of the upper face plate  203 , and the locking lugs  282  of the rear insertion chips  267  are folded and locked to the back face  226  of the upper face plate  203  thereby to mount the pair of metal rails  261 ,  261  to the rail track belt  202 . 
     Next, when the magnets  250 ,  250  are housed in the substantially rectangular magnet housing frames  230 ,  231 , the magnet  250  housed in the right magnet housing frame  230  comes in contact with the metal rail  261  in the insertion recessed portion  272  of the right metal rail  261  and the magnet  250  housed in the left magnet housing frame  231  comes in contact with the metal rail  261  in the insertion recessed portion  272  of the left metal rail  261 . The fitting pins  246  of the bottom plate  245  are fitted in the positioning holes  242  of the upper face plate  203  and the screws  248  are screwed into the internal thread portions  241  through the through holes  247  thereby to mount the bottom plate  245  to the rail track belt  202 . With the bottom plate  245 , the magnets  250  mounted to the magnet housing frames  230 ,  231  are fixed. 
     The insertion protruding portion  281  of the metal rail  261  mounted to the left groove  216  protrudes from the front face plate  210  and the insertion protruding portion  281  of the metal rail  261  mounted to the right groove  215  protrudes from the rear face plate  211 . In the metal rail  261  mounted to the right groove  215 , an insertion hole  290  is formed on the front face plate  210  side by the insertion recessed portion  272 , and the bottom face  219  and the side faces  218 ,  218  of the groove  215 . In the metal rail  261  mounted to the left groove  216 , an insertion hole  290  is formed on the rear face plate  211  side by the insertion recessed portion  272 , and the bottom face  219  and the side faces  218 ,  218  of the groove  216 . 
     As shown in  FIGS. 15(   a ) to  15 ( e ), if the front face plate  210  of the rail track belt  202  of the rail track device  201  is brought in contact with the rear face plate  211  of the rail track belt  202  of the other rail track device, the insertion protruding portions  281  are inserted into the insertion holes  290  and come in contact with the magnets  250 . With attracting forces of the magnets  250 , the rail track devices  201  are coupled to each other. In this way, the rail track devices  201  may be coupled in a straight line or ring shape. Because the magnets  250  have conductivity, it is possible to pass an electric current throughout the metal rails  261  of the rail track devices  201  coupled in the straight line or ring shape. 
     It is possible to place the drive wheel devices  1 ,  1  and the follower wheel devices  31 ,  31  of the powered toy vehicle  101  on the metal rails  261 ,  261  of the rail track device  201 . As shown in  FIG. 16 , the second wheel main bodies  21 ,  21  and the fourth wheel main bodies  51 ,  51  formed of the magnets alternately come in contact with the metal rails  261 ,  261 . A positive electrode of a power source is connected to one ( 261 A) of the metal rails  261  and a negative electrode of the power source is connected to the other ( 261 B) of the metal rails  261 . 
     The electric current flows from one ( 51 A) of the fourth wheel main bodies  51  which contacts with the metal rail  261 A to the metal rail  261 B via the conductive ring  60 , the first conductive contact  141 , the spring  155 , one of the spring retaining chips  156 , the positive terminal of the drive motor  116 , the negative terminal of the drive motor  116 , the other spring retaining chip  156 , the spring  155 , the second conductive contact  145 , the conductive ring  60 , and the other ( 51 B) of the fourth wheel main bodies  51 . With this electric current, the drive motor  116  rotates, the rotation is transmitted to the gears  8 ,  8  via the gear train  120 , and the drive wheel devices  1 ,  1  rotate on the metal rails  261 ,  261 . As a result, the powered toy vehicle  101  can travel on the rail track device  201 . 
     When the powered toy vehicle  101  is traveling on a curve, inner wheels try to rotate slowly and outer wheels try to rotate fast. Because the wheels not attracting with the magnets slip on the rails, there is less resistance of magnetic force and less load is applied on the drive motor  116  as compared with the conventional toy vehicle in which both the wheels rotate while being attracted to the magnets. 
     The toy passenger vehicle  161  is coupled to the powered toy vehicle  101  and the follower wheel devices  31 ,  31 ,  65 ,  65  of the toy passenger vehicle  161  can be placed on the metal rails  261 ,  261  of the rail track device  201 . The positive electrode of the power source is connected to one ( 261 A) of the metal rails  261  and the negative electrode of the power source is connected to the other ( 261 B) of the metal rails  261 . 
     An electric current flows from one ( 51 C) of the fourth wheel main bodies  51  in contact with the metal rail  261 A to the metal rail  261 B via the conductive ring  60 , the first conductive contact  141 , the spring  155 , one of the spring retaining chips  156 , the electric components such as the light emitting device, the other spring retaining chip  156 , the spring  155 , the second conductive contact  145 , the conductive ring  60 , and the other ( 51 D) of the fourth wheel main bodies  51 . With this electric current, the electric components in the toy vehicle main body  162  are actuated. 
     The powered toy vehicle  101  and the toy passenger vehicles  161 ,  171  are extremely small and travel on the metal rails  261 ,  261  at an interval of about 3 mm. Although the powered toy vehicle  101  and the toy passenger vehicles  161 ,  171  are extremely lightweight, the second wheel main bodies  21  of the drive wheel devices  1  and the fourth wheel main bodies  51  of the follower wheel devices  31  in contact with the metal rails  261  are formed of the magnets. Therefore, the second wheel main bodies  21  and the fourth wheel main bodies  51  attract the metal rails  261  with the magnetic forces, rotation of the drive wheel devices  1  and the follower wheel devices  31  is reliably transmitted to the metal rails  261  without slips, and the vehicles travel even on an upward slope. Moreover, because the second wheel main bodies  21  of the drive wheel devices  1  and the fourth wheel main bodies  51  of the follower wheel devices  31  are attracting the metal rails  261  with the magnetic forces, the vehicles do not come off and fall from the metal rails  261 . 
     If the insertion protruding portion  281  of the metal rail  261  of the other rail track belt  202  is inserted into the insertion recessed portion  272  of the rail track belt  202  of the rail track device  201 , the insertion protruding portion  281  of the other metal rail  261  is attracted to the magnet  250  and the metal rails  261  can be connected to the other metal rails  261  with the magnets  250  interposed therebetween. In this way, it is possible to couple the other rail track belt  202 . If the rail track belts  202  are pulled apart with forces greater than the magnetic forces of the magnets  250 , connection between the metal rails  261  and coupling between the rail track belts  202  of the rail track devices  201  can be cancelled easily. As seen from the above, the rail track devices  201  are functional and have simplified structures, because connection of the metal rails  261  and coupling of the rail track belts  202  by the magnets  250  can be carried out simultaneously and canceling of the connection and coupling can also be carried out simultaneously. Therefore, the rail track device  201  can be reduced in size and weight in such a way that the interval between the metal rails  261 ,  261  is as short as about 3 mm. Moreover, because the rail track devices  201  can be reduced in size and weight, the connection and coupling can be satisfactorily carried out with the magnetic forces of the magnets  250 . The method of manufacturing the rail track device  201  is extremely easy, because the metal rails  261 ,  261  can be fixed to the rail track belt  202  by only inserting the pair of metal rails  261 ,  261  into the pair of grooves  215 ,  216  in the rail track belt  202  and folding the locking lugs  275 ,  278 ,  279 , and  282  of the metal rails  261 ,  261 . 
     Other embodiments of the wheel devices for a toy vehicle according to the present invention and the toy vehicles mounted with the wheel devices will now be described based on  FIGS. 17(   a ) to  33 ( c ).  FIGS. 17(   a ) and  17 ( b ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention, wherein  FIG. 17(   a ) is a front view and  FIG. 17(   b ) is a sectional view.  FIGS. 18(   a ) to  20 ( b ) are general views of the other embodiments of the follower wheel device for a toy vehicle according to the present invention, wherein  FIGS. 18(   a ),  19 ( a ),  20 ( a ) are front views and  FIGS. 18(   b ),  19 ( b ),  20 ( b ) are sectional views.  FIGS. 21(   a ) and  21 ( b ) are exploded perspective views of the drive wheel devices for a toy vehicle according to the present invention mounted into a carriage, wherein  FIG. 21(   a ) is a perspective view from above and  FIG. 21(   b ) is a perspective view from below.  FIGS. 22(   a ) to  24 ( b ) are exploded perspective views of the follower wheel devices for a toy vehicle according to the present invention mounted into carriages, wherein  FIGS. 22(   a ),  23 ( a ),  24 ( a ) are perspective views from above and  FIGS. 22(   b ),  23 ( b ),  24 ( b ) are perspective views from below.  FIG. 25  is an exploded perspective view of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 26(   a ) and  26 ( b ) are sectional views of the wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle, wherein  FIG. 26(   a ) is a sectional view of an essential part when the drive wheel devices are mounted and  FIG. 26(   b ) is a sectional view of an essential part when the follower wheel devices are mounted.  FIGS. 27(   a ) and  27 ( b ) are assembly drawings of  FIG. 25 , wherein  FIG. 27(   a ) is a perspective view from above and  FIG. 27(   b ) is a perspective view from below.  FIG. 28  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 29(   a ) and  29 ( b ) are assembly drawings of  FIG. 28 , wherein  FIG. 29(   a ) is a perspective view from above and  FIG. 29(   b ) is a perspective view from below.  FIG. 30  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 31(   a ) and  31 ( b ) are assembly drawings of FIG.  30 , wherein  FIG. 31(   a ) is a perspective view from above and  FIG. 31(   b ) is a perspective view from below.  FIGS. 32(   a ) and  32 ( b ) are perspective views of a coupler.  FIGS. 33(   a ) to  33 ( c ) are explanatory views of the toy vehicles coupled by the couplers. 
     As shown in  FIGS. 17(   a ),  17 ( b ),  19 ( a ),  19 ( b ), the wheel device  301 ,  301 A for a toy vehicle is adapted to be placed on a pair of rails  561 ,  561  and includes a first axle  302 , and a first wheel  310  and a second wheel  320 ,  320 A provided on opposite sides of the first axle  302 . The first wheel  310  includes a first wheel main body  311  rolling on one of the rails  561 , and a first flange  312  guided by the one rail  561  and the first wheel main body  311  and the first flange  312  are made of a synthetic resin. The second wheel  320 ,  320 A includes a second wheel main body  321  rolling on the other rail  561  and a second flange  322  guided by the other rail  561  and at least the second wheel main body  321  is formed of a member attracting with a magnetic force. 
     The second wheel main body  321  may be formed of a magnet as shown in  FIGS. 41(   a ) and  41 ( b ). Preferably, the second wheel main body  321  includes a magnet  328  and a rolling shaft  330  mounted with the magnet  328  therein and formed in the shape of a round shaft. This is because directly forming a bearing portion is difficult on the magnet  328  but is easy on the rolling shaft  330  covering the magnet  328 . Moreover, the rolling shaft  330  is preferably made of ferromagnetic material. Although the rolling shaft  330  attracts the rail  561  with the magnet  328  mounted therein, the attracting force increases if the rolling shaft  330  is made of ferromagnetic material. 
     The first wheel main body  311 , the first flange  312 , the first axle  302 , and the second flange  322  of the wheel device  301 ,  301 A of the toy vehicle may be made of a synthetic resin. The wheel device  301  of the toy vehicle may be formed with a gear  308 . 
     As shown in  FIGS. 25 and 30 , a toy vehicle main body  402 , of a toy vehicle  401 ,  471  has a chassis  403 ,  473  and carriage frames  371 ,  371  mounted to front and rear portions of the chassis  403 ,  473 . The carriage frame  371  is provided with a pair of wheel devices  301 ,  301 A for a toy vehicle. The pair of wheel devices  301 ,  301 A is rotatably mounted onto the carriage frame(s)  371 ,  371  so that the second wheel main bodies  321  formed of the members attracting with the magnetic forces come in contact with different rails  561 . 
     As shown in  FIGS. 18(   a ) and  18 ( b ), a wheel device  331  for a toy vehicle is adapted to be placed on a pair of rails  561  and includes a second axle  332 , and a third wheel  340  and a fourth wheel  350  provided on opposite sides of the second axle  332 . The third wheel  340  includes a third wheel main body  341  rolling on one of the rails  561  and a third flange  342  guided by the one rail  561  and the third wheel main body  341  and the third flange  342  are made of a synthetic resin. The fourth wheel  350  includes a fourth wheel main body  351  rolling on the other rail  561  and a fourth flange  352  guided by the other rail  561 . The fourth wheel main body  351  includes the second axle  332  and is formed of a member attracting with a magnetic force. 
     The fourth wheel main body  351  may be formed of a magnet as shown in  FIGS. 42(   a ) and  41 ( b ). Preferably, the fourth wheel main body  351  includes a magnet  328 A and a rolling shaft  330 A having the magnet  328 A mounted therein and made of ferromagnetic material in the shape of a round shaft. This is because directly forming a bearing portion is difficult on the magnet  328 A but is easy on the rolling shaft  330 A covering the magnet  328 A. Moreover, the attracting force increases if the rolling shaft  330 A is made of the ferromagnetic material. 
     The third wheel main body  341 , the third flange  342 , the fourth flange  352  of the wheel device  331  of the toy vehicle may be made of a synthetic resin. The wheel device  331  of the toy vehicle is installed by a conductive ring  360  electrically conductive with the second axle  332  between the third wheel  340  and the fourth wheel  350 . 
     As shown in  FIG. 28 , a toy vehicle main body  462  of a toy vehicle  461  has a chassis  463  and carriage frames  371  mounted to front and rear portions of the chassis  463 . The carriage frames  371  are provided with a pair of wheel devices  331  of the toy vehicle. The pair of wheel devices  331  is rotatably mounted onto the carriage frames  371  so that the fourth wheel main bodies  351  formed of the members attracting with the magnetic forces come in contact with different rails  561 . 
     As shown in  FIG. 25 , a toy vehicle main body  402  of a toy vehicle  401  has a chassis  403  and carriage frames  371 ,  371  mounted to front and rear portions of the chassis  403 . The carriage frame  371  mounted to one of the front and rear portions is provided with the pair of wheel devices  301  of the toy vehicle. The carriage frame  371  mounted to the other of the front and rear portions is provided with the pair of wheel devices  331  of the toy vehicle. The chassis  403  is mounted with a drive motor  416  and a gear train  420  for transmitting rotation of the drive motor  416  to the gears  308  of the pair of wheel devices  301  of the toy vehicle. The chassis  403  is mounted with a first conductive contact  441  coming in sliding contact with one of the conductive rings  360  of the pair of wheel devices  331  for a toy vehicle and a second conductive contact  445  coming in sliding contact with the other conductive ring  360 . The first conductive contact  441  is electrically connected to one of a positive terminal and a negative terminal of the drive motor  416  and the second conductive contact  445  is electrically connected to the other of the positive terminal and the negative terminal of the drive motor  416 . 
     The second wheel main bodies  321  of the pair of wheel devices  301  of the toy vehicle and formed of the members attracting with the magnetic forces and the fourth wheel main bodies  351  of the pair of wheel devices  331  of the toy vehicle and formed of the members attracting with the magnetic forces are arranged to alternately come in contact with different rails  561 . 
     As shown in  FIG. 25 , the toy vehicle main body  402  of the toy vehicle  401  has the chassis  403  and the carriage frames  371  mounted to the front and rear portions of the chassis  403 . The carriage frame  371  mounted to the front or rear portion is provided with the pair of wheel devices  331  of the toy vehicle. The chassis  403  is mounted with an electric component  416 . The chassis  403  is provided with the first conductive contact  441  coming in sliding contact with one of the conductive rings  360  of the pair of wheel devices  331  for a toy vehicle and the second conductive contact  445  coming in sliding contact with the other conductive ring  360 . The first conductive contact  441  is electrically connected to one of a positive terminal and a negative terminal of the electric component  416  and the second conductive contact  445  is electrically connected to the other of the positive terminal and the negative terminal of the electric component  416 . 
     As shown in  FIG. 28 , the toy vehicle main body  462  of the toy vehicle  461  has the chassis  463  and the carriage frames  371 ,  371  mounted to the front and rear portions of the chassis  463 . The carriage frames  371  mounted to the front and rear portions are provided with the wheel devices  331  of the toy vehicle. The chassis  463  is provided with an electric component  446 . The chassis  463  is provided with a third conductive contact  441  coming in sliding contact with the conductive ring  360  of the front wheel device  331  for a toy vehicle and a fourth conductive contact  445  coming in sliding contact with the conductive ring  360  of the rear wheel device  331  of the toy vehicle. The third conductive contact  441  is electrically connected to one of a positive terminal and a negative terminal of the electric component  446  and the fourth conductive contact  445  is electrically connected to the other of the positive terminal and the negative terminal of the electric component  446 . 
     The drive wheel devices, the follower wheel devices, and the toy vehicles mounted with them will be described in further detail. As shown in  FIGS. 17(   a ),  17 ( b ),  21 ( a ),  21 ( b ), the drive wheel device  301  includes the first axle  302 , the first wheel  310 , and the second wheel  320 . The first axle  302  is made of a synthetic resin and formed into a cylindrical shape. One side face  303  of the first axle  302  is formed with a first round shaft recessed portion  305  coaxial with the first axle  302 . The other side face  306  of the first axle  302  is formed with a second round shaft recessed portion  307  coaxial with the first axle  302  and having a larger diameter than the first round shaft recessed portion  305 . A peripheral face of the first axle  302  is integrally formed with the gear  308 . Cog tips of the gear  308  are curved to form spherical surfaces. 
     The first wheel  310  includes the first wheel main body  311 , the first flange  312 , and a fitting shaft  313  and is integrally molded of a synthetic resin. An outer side face  315  of the first flange  312  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. The outer side face  315  of the first flange  312  is provided with the first wheel main body  311  substantially coaxial with the first flange  312 . An inner side face  316  of the first flange  312  is provided with the fitting shaft  313  substantially coaxial with the first flange  312 . A tip end face  318  of the first wheel main body  311  is formed with a substantially conical support recessed portion  314  substantially coaxial with the first wheel main body  311 . In the fitting shaft  313 , the first wheel  310  is fitted and fixed into the first round shaft recessed portion  305  of the first axle  302 . 
     The second wheel  320  includes the second wheel main body  321 , the second flange  322 , and a boss portion  323 . The second wheel main body  321  includes the magnet  328  and the rolling shaft  330  mounted with the magnet  328  therein and formed in the shape of the round shaft. The rolling shaft  330  is preferably made of a ferromagnetic material such as iron and formed in the shape of the round shaft having substantially the same outer diameter as the first wheel main body  311 . The rolling shaft  330  is formed therein with a housing recessed portion  333  coaxial with the rolling shaft  330 . Substantially at a center of one end face  335  of the rolling shaft  330  in an axial direction, a support hole  334  is formed. The other end face  336  of the rolling shaft  330  in the axial direction is formed with an opening  337  communicating with the housing recessed portion  333 . In the housing recessed portion  333  of the rolling shaft  330 , the magnet  328  in the shape of a round shaft is housed through the opening  337 . The magnet  328  is formed of a neodymium magnet, for example. An outer side face  325  of the second flange  322  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. An inner side face  326  of the second flange  322  is provided with the boss portion  323  substantially coaxial with the second flange  322  and having substantially the same outer diameter as the first axle  302 . The second flange  322  and the boss portion  323  are integrally molded of a synthetic resin. 
     The second flange  322  and the boss portion  323  are formed, substantially at centers thereof, with a through hole  327  having substantially the same inner diameter as the second round shaft recessed portion  307  of the first axle  302 . The second wheel main body  321  has substantially the same outer diameter as the first wheel main body  311 , passes through the through hole  327 , and is fixed with its opposite sides protruding from the second flange  322  and the boss portion  323 . The other end face  336  side of the rolling shaft  330  of the second wheel  320  protrudes from the boss portion  323  side and one end face  335  side of the rolling shaft  330  protrudes from the second flange  322  side. The second wheel  320  is fixed with a protruding portion  329  of the rolling shaft  330  (second wheel main body  321 ) protruding from the boss portion  323  side being fitted in the second round shaft recessed portion  307  of the first axle  302 . The gear  308  is in a substantially middle position between the first flange  312  and the second flange  322 . As described above, the drive wheel device  301  is made of a synthetic resin excluding the second wheel main body  321  that is formed of the member attracting with the magnetic force. Alternatively, as shown in  FIG. 41 , the second wheel main body  321  may be formed of a magnet in the shape of a round shaft and a tip end face  324   a  may be formed with a substantially conical support recessed portion  324  substantially coaxial with the second wheel main body  321 . 
     As shown in  FIGS. 19(   a ),  19 ( b ),  24 ( a ), and  24 ( b ), the wheel device (follower wheel device)  301 A has a structure where the first axle  302 , the first wheel  310 , the second flange  322 , and the boss portion  323  are integrally molded of a synthetic resin, and the second wheel main body  321  is fitted into a round shaft recessed portion  307 A formed in a side face of the second flange  322 . The second flange  322  and the second wheel main body  321  form the second wheel  320 A. As described above, the first wheel  310  has the first wheel main body  311  and the first flange  312 , and a tip end face  318  of the first wheel main body  311  is formed with a support recessed portion  314 . The second wheel  320 A has the second wheel main body  321  and the second flange  322 , the magnet  328  is provided in the second wheel main body  321 , and a support hole  334  is formed in one end face  335  of a rolling shaft  330  formed in the shape of a round shaft. Although the second wheel main bodies  321  of the drive wheel device  301  and the wheel device (follower wheel device)  301 A are made of ferromagnetic material such as iron, it is essential only that they be the members attracting the metal rails  261  with the magnetic forces. Therefore, the rolling shaft  330  may be made of a synthetic resin material. 
     As shown in  FIGS. 18(   a ),  18 ( b ),  22 ( a ), and  22 ( b ), the follower wheel device  331  includes the second axle  332 , the third wheel  340 , the fourth wheel  350 , and the conductive ring  360 . The second axle  332  is in the shape of a round shaft having substantially the same outer diameter as the first wheel main body  311  and includes the magnet  328 A and a rolling shaft  330 A mounted with the magnet  328 A therein and formed in the shape of a round shaft. The rolling shaft  330 A is made of ferromagnetic material such as iron and formed in the shape of the round shaft having substantially the same outer diameter as the first wheel main body  311 . The rolling shaft  330 A is formed therein with a housing recessed portion  333 A coaxial with the rolling shaft  330 A. Substantially at a center of one end face  335 A of the rolling shaft  330 A in an axial direction, a support hole  334 A is formed. The other end face  336 A of the rolling shaft  330 A in the axial direction is formed with an opening  337 A communicating with the housing recessed portion  333 A. In the housing recessed portion  333 A of the rolling shaft  330 A, the magnet  328 A in the shape of the round shaft is housed through the opening  337 A. The magnet  328 A is formed of a neodymium magnet, for example. 
     The third wheel  340  includes the third wheel main body  341 , the third flange  342 , and a boss portion  343  and is integrally molded of a synthetic resin. An outer side face  345  of the third flange  342  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. The outer side face  345  of the third flange  342  is attached to the third wheel main body  341  substantially coaxial with the third flange  342 . An inner side face  346  of the third flange  342  is provided with the boss portion  343  substantially coaxial with the third flange  342 . The boss portion  343  is formed, substantially at a center thereof, with a fitting hole  347  in which the other end face  336 A side of the second axle  332  is fitted. A tip end face  348  of the third wheel main body  341  is formed with a substantially conical support recessed portion  344  substantially coaxial with the third wheel main body  341 . The second axle  332  has substantially the same outer diameter as the third wheel main body  341  and is substantially coaxial with the third wheel main body  341 . 
     The fourth wheel  350  includes the fourth flange  352  and a boss portion  353 , and the fourth flange  352  and the boss portion  353  are integrally molded of a synthetic resin. An outer side face  355  of the fourth flange  352  slopes so that a wall thickness reduces from a center toward an outer peripheral edge. An inner side face  356  of the fourth flange  352  is provided with the boss portion  353  substantially coaxial with the fourth flange  352 . The fourth flange  352  and the boss portion  353  are formed, substantially at centers thereof, with a through hole  357  having substantially the same inner diameter as the fitting hole  347  of the third wheel  340 . The second axle  332  passes through the through hole  357  and is fixed with its opposite sides protruding from the fourth flange  352  and the boss portion  353 . The one end face  335 A of the second axle  332  protrudes from the fourth flange  352  side and a protruding portion  329  of the second axle  332  forms the fourth wheel main body  351  of the fourth wheel  350 . In other words, the fourth wheel main body  351  constitutes the second axle  332 . The fourth wheel main body  351 , the fourth flange  352 , and the boss portion  353  form the fourth wheel  350 . 
     Between the third wheel  340  (boss portion  343 ) and the fourth wheel  350  (boss portion  353 ) of the second axle  332  (fourth wheel main body  351 ), the conductive ring  360  conductive with the second axle  332  (fourth wheel main body  351 ) is mounted. The conductive ring  360  may be made of any kind of material, if it is made of a conductive material. In the embodiment, the conductive ring  360  is made of phosphor bronze. Although the conductive ring  360  is fixedly mounted to the second axle  332  (fourth wheel main body  351 ), it may be mounted rotatably. Although the fourth wheel main body  351  and the second axle  332  are made of the same material in the embodiment, the fourth wheel main body  351  may be made of a first conductive material with a magnetic property, the second axle  332  may be made of second conductive material to have a different outer diameter from the fourth wheel main body  351 , and the fourth wheel main body  351  and the second axle  332  may be provided to be adjacent to each other. Alternatively, as shown in  FIG. 42 , the second axle  332  (fourth wheel main body  351 ) may be formed of a magnet in the shape of a round shaft and a tip end face  354   a  may be formed with a substantially conical support recessed portion  354  substantially coaxial with the fourth wheel main body  351 . 
     As shown in  FIGS. 20(   a ),  20 ( b ),  23 ( a ), and  23 ( b ), a follower wheel device  365  includes an axle  366  and a pair of wheels  367  and is integrally molded of a synthetic resin. Each of the wheels  367  includes a wheel main body  368  and a flange  369 . A tip end face of the wheel main body  368  is formed, substantially at a center thereof, with a substantially conical support recessed portion  364 . The above-described drive wheel devices  301  and the follower wheel devices  301 A,  331 ,  365  are rotatably mounted to the carriage frames  371  for a toy vehicle as shown in  FIGS. 21(   a ) to  24 ( b ). The drive wheel devices  301  and the follower wheel devices  301 A,  331 ,  365  are mounted into the carriage frames  371  thereby to form carriages. 
     As shown in  FIGS. 21(   a ) and  21 ( b ), the carriage frame  371  is configured by a substantially rectangular main frame  372 , a middle member  373  for partitioning an inside of the main frame  372 , support protruding portions  384 , support shafts  385 , and locking lugs  393 , and the like, and is integrally molded of a synthetic resin. The main frame  372  is configured by a pair of longitudinal members  376 ,  376  in a longitudinal direction and a pair of lateral members  377 ,  377  in a lateral direction and provided at opposite ends of the longitudinal members  376 ,  376 . An outer face  378  of the lateral member  377  is formed of a convex curved face in the shape of an arc having a center substantially at a center of the main frame  372 . The outer face  378  of one of the lateral members  377  is formed, substantially at a center thereof, with a coupling hole  378 A. 
     The middle member  373  is provided to connect substantially central portions of the pair of longitudinal members  376 ,  376  and is mounted to lower faces  376 A,  376 A of the longitudinal members  376 ,  376  to be in positions lower than the lateral members  377 ,  377 . The middle member  373  forms housing portions  381 ,  382  for housing the wheel devices  301 ,  301 A,  331 ,  365  in the main frame  372 . The housing portions  381 ,  382  are provided with the support protruding portions  384  and the support shafts  385  facing each other. Each of the support protruding portions  384  is formed in a substantially conical shape and is fitted in the above-described support recessed portion  314  of the first wheel main body  311 , support recessed portion  344  of the third wheel main body  341 , or support recessed portion  364  of the wheel main body  368  so as to be rotatable. Each of the support shafts  385  is rotatably fitted in the above-described support hole  334  of the rolling shaft  330  or the support hole  334 A of the rolling shaft  330 A. The wheel devices  301 ,  301 A,  331 ,  365  have their support recessed portions  314 ,  344 ,  364 , rotatably supported by the support protruding portions  384  and their support holes  334 ,  334 A rotatably supported by the support shafts  385 . Because the support protruding portions  384  are formed to be larger than the support shafts  385  and cannot be inserted into the support holes  334 , which facilitates positioning of the wheel devices  301 ,  301 A,  331 ,  365  and prevents mounting to the carriage frames  371  in a wrong way. In the housing portion  381 , the support protruding portion  384  is formed at a support chip  386  formed on the lower face  376 A of one of the longitudinal members  376 . Similarly, in the housing portion  381 , the support shaft  385  is formed at a support chip  387  formed on the lower face  376 A of the other longitudinal member  376 . In the housing portion  382 , the support protruding portion  384  is formed at a support chip  386  formed on the lower face  376 A of the other longitudinal member  376 . Similarly, in the housing portion  382 , the support shaft  385  is formed at a support chip  387  formed on the lower face  376 A of the one longitudinal member  376 . Upper faces  377 B,  377 B of the lateral members  377 ,  377  are formed, substantially at centers thereof, with locking lugs  393 ,  393 . Upper faces  376 B,  376 B of the longitudinal members  376 ,  376  are formed, substantially at centers thereof, with guide protrusions  395 ,  395 . 
     As shown in  FIG. 25 , the toy vehicle main body  402  for the powered toy vehicle  401  includes the chassis  403  and a vehicle body  405  mounted to the chassis  403 . Formed at each of a front portion and a rear portion of the chassis  403  is a pair of curved locking grooves  410 ,  410  which are facing each other and to which the carriage frame  371  can be mounted. The carriage frame  371  is mounted with the pair of drive wheel devices  301 ,  301  which are rotatable so that the second wheel main bodies  321  are in opposite positions (coming in contact with different rails) as described above. The carriage frame  371  and the pair of drive wheel devices  301 ,  301  constitute the drive-side carriage  370 A. 
     As shown in  FIG. 25 , the drive-side carriage  370 A is mounted to the chassis  403  by locking the locking lugs  393 ,  393  of the carriage frame  371  to the locking grooves  410 ,  410 . When the carriage frame  371  is mounted to the chassis  403 , the guide protrusions  395 ,  395  protrude into guide grooves  408 ,  408  formed in the chassis  403  and the guide protrusions  395 ,  395  can rotate within areas in which they are guided by the guide grooves  408 ,  408 . 
     As shown in  FIG. 25 , the pair of follower wheel devices  331 ,  331  is rotatably mounted to the carriage frame  371  so that the fourth wheel main bodies  351  are in opposite positions (coming in contact with different rails). The carriage frame  371  and the pair of follower wheel devices  331 ,  331  constitute the follower-side carriage  370 B. The follower-side carriage  370 B is mounted similarly to the carriage  370 A. 
     The chassis  403  is provided with the drive motor  416  and the gear train  420  for transmitting rotation of the drive motor  416  to the gears  308 ,  308  of the pair of drive wheel devices  301 ,  301 . The gear train  420  consists of a drive gear  421  mounted to a drive shaft of the drive motor  416 , a crown gear  422  engaged with the drive gear  421 , a small gear integral with the crown gear  422 , a large gear  425  engaged with the small gear integral with the crown gear  422 , a small gear  426  integral with the large gear  425 , a large gear  427  engaged with the small gear  426 , a small gear integral with the large gear  427 , a large gear  429  engaged with the small gear integral with the large gear  427 , a small gear  428  integral with the large gear  429 , and a final gear  430  integral with the small gear  428 . Cog tips of the final gear  430  are curved into spherical surfaces. 
     The chassis  403  is mounted with a gear box  431  in which the crown gear  422 , the small gear integral with the crown gear  422 , the large gear  425 , the small gear  426 , the large gear  427 , the small gear integral with the large gear  427 , the large gear  429 , the small gear  428 , and the final gear  430  are rotatably mounted. The final gear  430  is adapted to be placed above the pair of gears  308 ,  308  of the carriage  370 A mounted to the chassis  403 . The chassis  403  is formed with an opening  433  for allowing the final gear  430  to protrude from the lower face of the chassis  403  and the final gear  430  protruding from the opening  433  is engaged with the gears  308 ,  308  of the drive wheel devices  301 ,  301  mounted to the carriage  370 A. 
     The chassis  403  is provided with the conductive contacts  441 ,  445  positioned above the follower wheel devices  331 ,  331  of the carriage  370 B. The conductive contacts  441 ,  445  are spring members made of conductive metal. The conductive contacts  441 ,  445  are mounted in cylindrical guide members  451 ,  451  formed on an upper portion of the chassis  403 . Upper ends of the conductive contacts  441 ,  445  come in contact with contact terminals  455 ,  456 . The contact terminals  455 ,  456  are formed of conductive metal sheets. 
     As shown in  FIG. 26(   b ), formed to protrude inside the vehicle body  405  are protrusions  459 ,  459  to be inserted into through holes  457 ,  458  formed in the contact terminals  455 ,  456  to fix the contact terminals  455 ,  456  when the vehicle body  405  is mounted to the chassis  403 . The chassis  403  is formed with openings  454  for allowing the conductive contacts  441 ,  445  to protrude from the lower face of the chassis  403 . Lower ends of the conductive contacts  441 ,  445  protrude from the openings  454  and come in sliding contact with the conductive rings  360 ,  360  of the follower wheel devices  331 ,  331  mounted to the carriage  370 B. One of the contact terminals  455 ,  456  is electrically connected to the positive terminal of the drive motor  416  and the other of the contact terminals  455 ,  456  is electrically connected to the negative terminal of the drive motor  416 . 
     As shown in  FIGS. 28 ,  29 ( a ), and  29 ( b ), the toy vehicle main body  462  of the toy passenger vehicle  461  includes the chassis  463  and a vehicle body  465  mounted to the chassis  463 . Formed at each of a front portion and a rear portion of the chassis  463  is a pair of curved locking members  410 ,  410  which are facing each other and to which the carriage frame  371  can be mounted. 
     As shown in  FIG. 28 , the follower wheel devices  331 ,  365  are rotatably mounted to the carriage frame  371  to form the follower-side carriage  370 C. The follower-side carriage  370 C is mounted to the chassis  403  by locking the locking lugs  393 ,  393  of the carriage frame  371  in the locking grooves  410 ,  410 . When the carriage frame  371  is mounted to the chassis  463 , guide protrusions  395 ,  395  protrude into guide grooves  408 ,  408  formed in the chassis  463  and the guide protrusions  395 ,  395  are rotatable within areas in which they are guided by the guide grooves  408 ,  408 . The follower wheel device  331  of one of the pair of carriages  370 C,  370 C and the follower wheel device  331  of the other are rotatably mounted to the carriage frames  371  so that the fourth wheel main bodies  351  are in opposite positions (coming in contact with different rails). 
     The chassis  463  is provided with the conductive contacts  441 ,  445  positioned above the follower wheel devices  331  of the carriages  370 C. The conductive contacts  441 ,  445  are mounted in cylindrical guide members  451  formed on an upper portion of the chassis  463 . One of the conductive contacts  441 ,  445  is electrically connected to a positive terminal of an electronic substrate  466  provided in the vehicle body  465  and the other of the conductive contacts  441 ,  445  is electrically connected to a negative terminal of the electronic substrate  466 . 
     The chassis  463  is formed with openings for allowing lower ends of the conductive contacts  441 ,  445  to protrude from the lower face of the chassis  463 . The lower ends of the conductive contacts  441 ,  445  protruding through the openings come in sliding contact with the conductive rings  360 ,  360  of the follower wheel devices  331 ,  331  mounted to the carriages  370 C. The electronic substrate  466  is provided with electric components, for example, a light emitting device such as an LED and a sound generating device. 
     As shown in  FIGS. 30 ,  31 ( a ), and  31 ( b ), a toy passenger vehicle  471  has basically the same structure as the toy passenger vehicle  461 , but a chassis  473  is not formed with the guide members  451 ,  451 , because there is no electric component, in a toy vehicle main body  472 , actuated by power fed from the rails. Therefore, the follower wheel devices  301 A,  365  are rotatably mounted to the carriage frame  371  thereby to form a follower-side carriage  370 D. The follower-side carriage  370 D is mounted to the chassis  473  by locking locking lugs  393 ,  393  of the carriage frame  371  in the locking grooves  410 ,  410 . When the carriage frame  371  is mounted to the chassis  473 , guide protrusions  395 ,  395  protrude into guide grooves  408 ,  408  formed in the chassis  473  and the guide protrusions  395 ,  395  can rotate within areas in which they are guided by the guide grooves  408 ,  408 . The follower wheel device  301 A of one of the pair of carriages  370 D,  370 D and the follower wheel device  301 A of the other are rotatably mounted to the carriage frames  371  so that the second wheels  320 A are in opposite positions (coming in contact with different rails). 
     The powered toy vehicle  401  and the toy passenger vehicles  461 ,  471  are coupled by a coupler  481 . As shown in  FIGS. 32(   a ),  32  ( b ), the coupler  481  is integrally formed of a synthetic resin and includes a coupling shaft  482  and a design member  483  formed substantially at a center of the coupling shaft  482 . As shown in  FIGS. 33(   a ) to  33 ( c ), the coupling shaft  482  couples the powered toy vehicle  401  and the toy passenger vehicle  461  by detachably inserting one end  484  of the coupling shaft  482  into the coupling hole  378 A of the carriage  370 B disposed at the rear portion of the powered toy vehicle  401  and detachably inserting the other end  485  of the coupling shaft  482  into the coupling hole  378 A of the carriage  370 C disposed at the front portion of the toy passenger vehicle  461 . The coupling shaft  482  couples the toy passenger vehicle  461  and the toy passenger vehicle  471  by detachably inserting one end  484  of the coupling shaft  482  into the coupling hole  378 A of the carriage  370 C disposed at the rear portion of the toy passenger vehicle  461  and detachably inserting the other end  485  of the coupling shaft  482  into the coupling hole  378 A of the carriage  370 D disposed at the front portion of the toy passenger vehicle  471 . In this way, it is possible to couple the respective toy vehicles. 
     Next, a rail track device according to the present invention will be described based on  FIGS. 34 to 40(   b ).  FIG. 34  is a perspective view of another embodiment of the rail track device according to the present invention.  FIG. 35  is an exploded perspective view of  FIG. 34 .  FIGS. 36(   a ) and  36 ( b ) are explanatory views of the rail track device, wherein  FIG. 36(   a ) is a plan view and  FIG. 36(   b ) is a side view.  FIGS. 37(   a ) to  37 ( c ) are explanatory views of the rail track device, wherein  FIG. 37(   a ) is a sectional view,  FIG. 37(   b ) is a bottom view, and  FIG. 37(   c ) is a side sectional view.  FIGS. 38(   a ) to  38 ( c ) are explanatory views of the rail track device from which a bottom plate is detached and which is viewed from below.  FIG. 39  is an explanatory view illustrating a relationship between a rail track belt and metal rails.  FIGS. 40(   a ) and  40 ( b ) are explanatory views of the metal rail. 
     As shown in  FIGS. 34 and 35 , the rail track device  501  includes a rail track belt  502  made of a synthetic resin and a pair of metal rails  561 ,  561  to be inserted into a pair of grooves  515 ,  516  formed in the rail track belt  502 . Each of the metal rails  561  is formed with an insertion recessed portion  572  at one end and an insertion protruding portion  581  at the other end. The rail track belt  502  is formed at one sides of ends thereof with mounting portions  530 ,  531  to which magnets  550  having conductivity are mounted. The magnets  550  mounted to the mounting portions  530 ,  531  are structured to be located in such positions as to be in contact with the metal rails  561 . The rail track belt  502  is structured to be connected to the other rail track belt  502  in such a way that, when an insertion protruding portion  581  of the metal rail  561  of the other rail track belt  502  is inserted into the insertion recessed portion  572  of the metal rail  561 , the other metal rail  561  come in contact with and is attracted by the magnet  550  thereby to connect the metal rail  561  to the other metal rail  561 . 
     As shown in  FIG. 39 , a method of manufacturing the rail track device  501  includes a first step of inserting the pair of metal rails  561 ,  561  into the pair of grooves  515 ,  516  in the rail track belt  502  made of a synthetic resin, inserting insertion chips  563 ,  565 ,  566 ,  567  of the pair of metal rails  561 ,  561  into the insertion holes  521 ,  522 ,  523 ,  524  in the rail track belt  502 , and locking locking lugs  571 ,  574 ,  575 ,  576 ,  578 ,  579  of the insertion chips  563 ,  565 ,  566 ,  567  to the insertion holes  521 ,  522 ,  523 ,  524  to fix the pair of metal rails  561 ,  561  to the rail track belt  502 , a second step of mounting the magnets  550  to the mounting portions  530 ,  531  formed at the one sides of the ends of the rail track belt  502 , and a third step of mounting the bottom plate  545  to a bottom portion of the rail track belt  502 . 
     As shown in  FIGS. 34 and 35 , the rail track device  501  includes the rail track belt  502  made of a synthetic resin and the pair of metal rails  561 ,  561 . The rail track belt  502  is configured by an upper face plate  503 , a right slope plate  505  arranged to be connected to a right side of the upper face plate  503 , a left slope plate  506  provided to be adjacent to a left side of the upper face plate  503 , a right side plate  507  provided to be adjacent to a lower end of the right slope plate  505 , a left side plate  508  provided to be adjacent to a lower end of the left slope plate  506 , a front face plate  510  provided to be adjacent to a front end of the upper face plate  503 , and a rear face plate  511  provided to be adjacent to a rear end of the upper face plate  503 . The rail track belt  502  is formed to be hollow and in a trapezoidal shape when viewed from the front. 
     The upper face plate  503  of the rail track belt  502  is formed with protrusions  513  in the shape of a cross tie. The upper face plate  503  is formed with the pair of grooves  515 ,  516  into which the pair of metal rails  561 ,  561  is inserted. Each of the grooves  515 ,  516  is formed being surrounded by side faces  518 ,  518  and a bottom face  519  into a substantially angular U shape. As shown in  FIG. 39 , the bottom faces  519  are formed, at predetermine portions thereof, with the insertion holes  521 ,  522 ,  523 ,  524 . The right groove  515  is formed with the insertion holes  521 ,  522 ,  523 ,  524  in this order from the front face plate  510  side and the left groove  516  is formed with the insertion holes  521 ,  522 ,  523 ,  524  in this order from the rear face plate  511  side. 
     As shown in  FIG. 39 , a back face  526  of the upper face plate  503  is formed with the pair of substantially L-shaped magnet housing frames  530 ,  531 . The right magnet housing frame  530  is formed along the right side plate  507  and the front face plate  510  and the left magnet housing frame  531  is formed along the left side plate  508  and the rear face plate  511 . The magnet housing frame  530  is formed with an insertion groove  532  into which the metal rail  561  is to be inserted. The magnet housing frame  531  is formed with an insertion groove  535  into which the metal rail  561  is to be inserted. The magnet  550  is pushed and mounted into each of the magnet housing frames  530 ,  531 . The magnets  550  are formed of material having conductivity such as neodymium magnets. Formed at opposite two positions of the back face  526  of the upper face plate  503  are bosses  540  each formed with an internal thread portion  541 . Moreover, formed at three positions of the back face  526  of the upper face plate  503  are bosses  543  each formed with a positioning hole  542 . 
     As shown in  FIG. 35 , the rail track belt  502  has the bottom plate  545  mounted to a hollow chamber surrounded with the front face plate  510 , the rear face plate  511 , the right side plate  507 , and the left side plate  508 . The bottom plate  545  is formed, substantially at a center thereof, with a recessed step portion  545   a . The bottom plate  545  is formed, at opposite sides, with fitting pins  546  to be fitted in the positioning holes  542  of the upper face plate  503 . A fitting hole  545   b  in which the boss  543  is to be fitted is formed at the recessed step portion  545   a . The bottom plate  545  is formed with through holes  547  facing the internal thread portions  541  of the upper face plate  503 . The bottom plate  545  is mounted to the rail track belt  502  by fitting the fitting pins  546  in the positioning holes  542  of the upper face plate  503 , fitting the boss  543  in the fitting hole  545   b , and screwing screws  248  into the internal thread portions  541  through the through holes  547 . The magnets  550  mounted to the magnet housing frames  530 ,  531  are prevented by the bottom plate  545  from coming off the magnet housing frames  530 ,  531 . 
     Each of the metal rails  561  is formed to have substantially the same length as the rail track belt  502 , has contact faces to come in contact with the bottom face  519  of the groove  515  or  516 , and is formed with a front insertion chip  563  to be inserted into the insertion hole  521  and the insertion groove  532  of the groove  515  or  516 , a first middle insertion chip  565  to be inserted through the insertion hole  522  of the groove  515  or  516 , a second middle insertion chip  566  to be inserted through the insertion hole  523  of the groove  515  or  516 , and a rear insertion chip  567  to be inserted through the insertion hole of the groove  515  or  516 . 
     As shown in  FIGS. 38(   a ) to  38 ( c ), the front insertion chip is formed with the locking lug  571  at its rear portion and the insertion recessed portion  572  at its front portion. The magnets  550  mounted to the magnet housing frames  530 ,  531  are in contact with side faces of the front insertion chips  563 . The first middle insertion chip  565  is formed with the locking lug  574  at its front portion and the locking lug  575  at its rear portion. The second middle insertion chip  566  is formed with the locking lug  576  at its front portion and the locking lug  578  at its rear portion. The rear insertion chip  567  is formed with the locking lug  579  at its front portion and is formed, at its rear portion, with the insertion protruding portion  581  that can be inserted into the insertion recessed portion  572  of the front insertion chip  563 . 
     The pair of metal rails  561  is pushed into the grooves  515 ,  516  of the rail track belt  502  in opposite orientations to each other. The contact faces  562  come in contact with the bottom face  519 , the front insertion chips  563  are inserted into the insertion holes  521 ,  532 , of the grooves  515 ,  516 , the first middle insertion chips  565  are inserted through the insertion holes  522  of the grooves  515 ,  516 , the second middle insertion chips  566  are inserted through the insertion holes  523  of the grooves  515 ,  516 , and the rear insertion chips  567  are inserted through the insertion holes  524  of the grooves  515 ,  516 . As shown in  FIGS. 40(   a ), and  40 ( b ), when the front insertion chip  563  is inserted into the insertion hole  521 , the locking lug  571  is locked to the back face  526  of the upper face plate  503 . When the first middle insertion chip  565  is inserted into the insertion hole  522 , the locking lugs  574 ,  575  are locked to the back face  526  of the upper face plate  503 . When the second middle insertion chip  566  is inserted into the insertion hole  523 , the locking lugs  576 ,  578  are locked to the back face  526  of the upper face plate  503 . When the rear insertion chip  567  is inserted into the insertion hole  524 , the locking lug  579  is locked to the back face  526  of the upper face plate  503 . The rear insertion chip  567  comes in contact with the magnet housing frames  530 ,  531  but not with the magnets  550 . As described above, it is possible to mount the pair of metal rails  261 ,  261  to the rail track belt  502  by only inserting the rails into the grooves  515 ,  516 . If the back face  526  of the upper face plate  503  is formed with guide protrusions  527 ,  528  for guiding the front insertion chips  563 , the first middle insertion chips  565 , the second middle insertion chips  566 , and the rear insertion chips  567  as shown in  FIG. 38(   a ) to  38 ( c ), it is possible to stably retain the metal rails  561 . 
     Next, when the magnets  550 ,  550  are housed in the substantially L-shaped magnet housing frames  530 ,  531 , the magnet  550  housed in the right magnet housing frame  530  comes in contact with the side face of the front insertion chip  563  of the right metal rail  561  and the magnet  550  housed in the left magnet housing frame  531  comes in contact with the side face of the front insertion chip  563  of the left metal rail  561 . The fitting pins  546  of the bottom plate  545  are fitted in the positioning holes  542  of the upper face plate  503 , the boss  543  is fitted in the fitting hole  545   b  of the bottom plate  545 , and the screws  248  are screwed into the internal thread portions  541  through the through holes  547  thereby to mount the bottom plate  545  to the rail track belt  502 . With the bottom plate  545 , the magnets  550  mounted to the magnet housing frames  530 ,  531  are fixed. 
     As shown in  FIG. 34 , the insertion protruding portion  581  of the metal rail  561  mounted to the left groove  516  protrudes from the front face plate  510  and the insertion protruding portion  581  of the metal rail  561  mounted to the right groove  515  protrudes from the rear face plate  511 . In the metal rail  561  mounted to the right groove  515 , an insertion hole  590  is formed on the front face plate  510  side by the insertion recessed portion  572 , and the bottom face  519  and the side faces  518 ,  518  of the groove  515 . In the metal rail  561  mounted to the left groove  516 , an insertion hole  590  is formed on the rear face plate  511  side by the insertion recessed portion  572 , and the bottom face  519  and the side faces  518 ,  518  of the groove  516 . 
     As shown in  FIGS. 36(   a ) to  37 ( b ), if the front face plate  510  of the rail track belt  502  of the rail track device  501  is brought in contact with the rear face plate  511  of the rail track belt  502  of the other rail track device, the insertion protruding portions  581  are inserted into the insertion holes  590  and the side faces of the insertion protruding portions  581  come in contact with the magnets  550 . With attracting forces of the magnets  550 , the rail track devices  501  are coupled to each other and the insertion protruding portions  581  and the insertion recessed portions  572  of the metal rails  561  come in direct contact with each other. In this way, the rail track devices  501  may be coupled in a straight line or ring shape. Because the metal rails  561  of the rail track devices  501  coupled in the straight line or ring shape are in direct contact with each other as described above, it is possible to pass an electric current throughout the rails. Even if the metal rails  561  are not in direct contact with each other, the metal rails  561  are electrically connected through the magnets  550  having conductivity and therefore it is possible to pass an electric current throughout the rails. 
     It is possible to place the drive wheel devices  301 ,  301  and the follower wheel devices  331 ,  331  of the powered toy vehicle  401  on the metal rails  561 ,  561  of the rail track device  501 . As shown in  FIG. 16 , the second wheel main bodies  321 ,  321  and the fourth wheel main bodies  351 ,  351  formed of the members attracting with magnetic forces alternately come in contact with the metal rails  561 ,  561 . A positive electrode of a power source is connected to one ( 561 A) of the metal rails  561  and a negative electrode of the power source is connected to the other ( 561 B) of the metal rails  561 . 
     The electric current flows from one of the fourth wheel main bodies  351  ( 351 A) in contact with the metal rail  561 A to the metal rail  561 B via the conductive ring  360 , the first conductive contact  441 , one of the contact terminals  455 , the positive terminal of the drive motor  416 , the negative terminal of the drive motor  416 , the other contact terminal  456 , the second conductive contact  445 , the conductive ring  360 , and the other of the fourth wheel main bodies  351  ( 351 B) as shown in  FIG. 25 . With this electric current, the drive motor  416  rotates, the rotation is transmitted to the gears  308 ,  308  via the gear train  420 , and the drive wheel devices  301 ,  301  rotate on the metal rails  561 ,  561 . As a result, the powered toy vehicle  401  can travel on the rail track device  501 . 
     When the powered toy vehicle  401  is traveling on a curve, inner wheels try to rotate slowly and outer wheels try to rotate fast. Because the wheels not affected by the magnets slip on the rails, there is less resistance of magnetic force and less load is applied on the drive motor  416  as compared with the conventional toy vehicle in which both the wheels rotate while attracting with the magnets. 
     The toy passenger vehicle  461  is coupled to the powered toy vehicle  401  as described above and the follower wheel devices  331 ,  331 ,  365 ,  365  of the toy passenger vehicle  461  can be placed on the metal rails  561 ,  561  of the rail track device  501 . The positive electrode of the power source is connected to one of the metal rails  561  ( 561 A) and the negative electrode of the power source is connected to the other of the metal rails  561  ( 561 B) 
     An electric current flows from one ( 351 C) of the fourth wheel main bodies  351  in contact with the metal rail  561 A to the metal rail  561 B via the conductive ring  360 , the first conductive contact  441 , the electronic substrate  466 , the second conductive contact  445 , the conductive ring  360 , and the other ( 351 D) of the fourth wheel main bodies  351 . With this electric current, an electric component of the electronic substrate  466  is actuated. 
     The powered toy vehicle  401  and the toy passenger vehicles  461 ,  471  are extremely small and travel on the metal rails  561 ,  561  at an interval of about 3 mm. Although the powered toy vehicle  401  and the toy passenger vehicles  461 ,  471  are extremely lightweight, the second wheel main bodies  321  of the drive wheel devices  301  and the fourth wheel main bodies  351  of the follower wheel devices  331  in contact with the metal rails  561  are formed of the members attracting with the magnetic forces. Therefore, the second wheel main bodies  321  and the fourth wheel main bodies  351  attract the metal rails  561  with the magnetic forces, rotation of the drive wheel devices  301  and the follower wheel devices  331  is reliably transmitted to the metal rails  561  without slips, and the vehicles travel even an upward slope. Moreover, because the second wheel main bodies  321  of the drive wheel devices  301  and the fourth wheel main bodies  531  of the follower wheel devices  331  are attracting the metal rails  561  with the magnetic forces, the vehicles do not come off and fall from the metal rails  561 . 
     If the insertion protruding portion  581  of the metal rail  561  of the other rail track belt  502  is inserted into the insertion recessed portion  572  of the rail track belt  502  of the rail track device  501 , the insertion protruding portion  581  of the other metal rail  561  comes in contact with and is attracted by the magnet  550  and the metal rails  561  can be directly connected to the other metal rails  561  by the magnets  550 . In this way, it is possible to couple the other rail track belt  502 . If the rail track belts  502  are pulled apart with forces greater than the magnetic forces of the magnets  550 , connection between the metal rails  561  and coupling between the rail track belts  502  of the rail track devices  501  can be cancelled easily. As seen from the above, the rail track devices  501  are functional and have simplified structures, because connection of the metal rails  561  and coupling of the rail track belts  502  by the magnets  550  can be carried out simultaneously and canceling of the connection and coupling can also be carried out simultaneously. Therefore, the rail track device  501  can be reduced in size and weight in such a way that the interval between the metal rails  561 ,  561  is as short as about 3 mm. Because the rail track device  501  can be reduced in size and weight, the magnetic forces of the magnets  550  are sufficient for connection and coupling. The method of manufacturing the rail track device  501  is extremely easy, because the metal rails  561 ,  561  can be fixed to the rail track belt  502  by only inserting the pair of metal rails  561 ,  561  into the pair of grooves  515 ,  516  in the rail track belt  502 . 
     Other embodiments of the wheel devices for a toy vehicle according to the present invention and the toy vehicles mounted with the wheel devices will be described based on  FIGS. 43(   a ) to  47 .  FIGS. 43(   a ) to  43 ( c ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention, wherein  FIG. 43(   a ) is a sectional view,  FIG. 43(   b ) is a front view, and  FIG. 43(   c ) is a perspective view.  FIGS. 44(   a ) to  45 ( c ) are general views of other embodiments of the follower wheel device for a toy vehicle according to the present invention, wherein  FIGS. 44(   a ),  45 ( a ) are sectional views,  FIGS. 44(   b ),  45 ( b ) are front views, and  FIGS. 44(   c ),  45 ( c ) are perspective views.  FIGS. 46 ,  47  are exploded perspective views of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into toy vehicles. 
     The drive wheel device, the follower wheel device, and the toy vehicle mounted with them will be described further in detail. As shown in  FIG. 43 , the drive wheel device  601  includes a first axle  602 , a first wheel  610 , and a second wheel  620 . The first axle  602  is made of a synthetic resin material such as ABS resin and formed into a cylindrical shape. To a peripheral face of the first axle  602 , a cylindrical member  605  having a gear  608  is secured. The cylindrical member  605  is made of a synthetic resin material such as polyacetal (POM). Cog tips of the gear  608  are curved to form spherical surfaces. 
     The first wheel  610  includes a first wheel main body  611  and a magnet ring  617 . The first wheel main body  611  includes a mounting shaft  619 , a first flange  612 , and a fitting shaft  613  and is integrally molded as a metal member such as an iron member. The first flange  612  is attached with the mounting shaft  619  substantially coaxial with the first flange  612  at an outer side face  615  thereof. The first flange  612  is provided, at an inner side face  616  thereof, with the fitting shaft  613  substantially coaxial with the first flange  612 . A tip end face  618  of the mounting shaft  619  is formed with a substantially conical support recessed portion  614  substantially coaxial with the first wheel main body  611 . To an outer peripheral face of the mounting shaft  619 , the magnet ring  617  is fixedly mounted to come in contact with the first flange  612 . The magnet ring  617  has a smaller outer diameter than the first flange  612 . The first wheel  610  is fixed with its fitting shaft  613  fitted into the first axle  602 . Since the second wheel  620  has the same structure as the first wheel  610 , description of the second wheel  620  will not be made here. The magnet rings  617 ,  617  function as wheels traveling on the rails  561 ,  561 . 
     As shown in  FIGS. 44(   a ) to  44 ( c ), the follower wheel device  631  includes a second axle  632 , a third wheel  640 , and a fourth wheel  650 . The second axle  632  is formed of a metal member such as a copper member into a cylindrical shape and has a similar function to the above-described conductive ring  360 . The third wheel  640  includes a third wheel main body  641  and a magnet ring  647 . The third wheel main body  641  includes a mounting shaft  649 , a third flange  642 , and a fitting shaft  643  and is integrally molded as a metal member such as a copper member. The third flange  642  is attached with the mounting shaft  649  substantially coaxial with the third flange  642  at an outer side face  645  thereof. The third flange  642  is attached with the fitting shaft  643  substantially coaxial with the third flange  642  at an inner side face  646  thereof. A tip end face  648  of the mounting shaft  649  is formed with a substantially conical support recessed portion  644  substantially coaxial with the third wheel main body  641 . To an outer peripheral face of the mounting shaft  649 , the magnet ring  647  is fixedly mounted to come in contact with the third flange  642 . The magnet ring  647  has a smaller outer diameter than the third flange  642 . The third wheel  640  is fixed with its fitting shaft  643  fitted into the second axle  632 . 
     The fourth wheel  650  includes a fourth wheel main body  651 , a fourth flange  652 , and a fitting shaft  653  and is integrally formed of a metal member such as a copper member. The fourth flange  652  is installed by the fourth wheel main body  651  substantially coaxial with the fourth flange  652  at an outer side face  655  thereof. The fourth flange  652  is attached with the fitting shaft  653  substantially coaxial with the fourth flange  652  at an inner side face  656  thereof. A tip end face  658  of the fourth wheel main body  651  is formed with a substantially conical support recessed portion  654  substantially coaxial with the fourth wheel main body  651 . The fourth flange  652  has substantially the same outer diameter as the third flange  642 . The fourth wheel main body  651  has substantially the same outer diameter as the magnet ring  647 . The fourth wheel  650  is mounted to an auxiliary member  661 . The auxiliary member  661  is constituted by a cylindrical trunk portion  662  and a locking flange  663  formed at one end of the trunk portion  662  and is integrally molded of a synthetic resin material such as ABS resin. The locking flange  663  has substantially the same outer diameter as the fourth flange  652 . The fourth wheel  650  is fixedly mounted to the auxiliary member  661  with the fitting shaft  653  fitted in the trunk portion  662  on the locking flange  663  side and the fourth flange  652  joined to the locking flange  663 . The auxiliary member  661  is fixed with the trunk portion  662  inserted into the second axle  632  until the locking flange  663  is locked to an end face of the second axle  632 . In this way, in the follower wheel device  631 , the third wheel  640  and the fourth wheel  650  are mounted to opposite sides of the second axle  632 . 
     As shown in  FIGS. 45(   a ) to  45 ( c ), the follower wheel device  671  includes a second axle  672  and the pair of fourth wheels  650 . The second axle  672  is formed of a synthetic resin material such as ABS resin into a cylindrical shape. Each of the fourth wheels  650  is fixedly mounted to the second axle  672  with the fitting shaft  653  fitted in the second axle  672  and the fourth flange  652  joined to an end face of the second axle  672 . 
     As shown in  FIGS. 46 and 47 , the above-described drive wheel device  601 , and the follower wheel devices  631 ,  671  are rotatably mounted to the carriage frames  371  of the toy vehicles. The drive wheel device  601 , the follower wheel devices  631 ,  671  are mounted into the carriage frames  371  to form the carriages. 
     As shown in  FIG. 46 , the pair of drive wheel devices  601 ,  601  is rotatably mounted to the carriage frame  371  of the powered toy vehicle  401  so that the first wheel main bodies  611  are in opposite positions (coming in contact with different rails). The carriage frame  371  and the pair of drive wheel devices  601 ,  601  form the drive-side carriage  370 A. 
     As shown in  FIG. 46 , the drive-side carriage  370 A is mounted to the chassis  403  by locking the locking lugs  393 ,  393  of the carriage frame  371  to the locking grooves  410 ,  410 . When the carriage frame  371  is mounted to the chassis  403 , the guide protrusions  395 ,  395  protrude into guide grooves  408 ,  408  formed in the chassis  403  and the guide protrusions  395 ,  395  can rotate within areas in which they are guided by the guide grooves  408 ,  408 . 
     As shown in  FIG. 46 , the pair of follower wheel devices  631 ,  631  is rotatably mounted to the carriage frame  371  of the powered toy vehicle  401  so that the third wheel main bodies  641  are in opposite positions (coming in contact with different rails). The carriage frame  371  and the pair of follower wheel devices  631 ,  631  form the follower-side carriage  370 B. The follower-side carriage  370 B is mounted similarly to the carriage  370 A. 
     The chassis  403  is provided with the drive motor  416  and a gear train  420 A for transmitting rotation of the drive motor to the gears  608 ,  608  of the pair of drive wheel devices  601 ,  601 . The gear train  420 A consists of a drive gear  421  mounted to a drive shaft of the drive motor  416 , a crown gear engaged with the drive gear  421 , a small gear  423  integral with the crown gear  422 ; a large gear  429  engaged with the small gear  423 , a small gear  428  integral with the large gear  429 , and a final gear  430  integral with the small gear  428 . Cog tips of the final gear  430  are curved into spherical surfaces. 
     The chassis  403  is mounted with a gear box  431 A with which the gear train  420 A is rotatably mounted on the chassis  403 . The final gear  430  is adapted to be placed above the pair of gears  608 ,  608  of the carriage  370 A mounted onto the chassis  403 . The chassis  403  is formed with an opening  433  for allowing the final gear  430  to protrude through the lower face of the chassis  403  and the final gear  430  protruding through the opening  433  is engaged with the gears  608 ,  608  of the drive wheel devices  601 ,  601  mounted to the carriage  370 A. As shown in  FIG. 46 , lower ends of the conductive contacts  441 ,  445  protrude from the openings  454  to come in sliding contact with the second axles  632 ,  632  of the follower wheel devices  631 ,  631  mounted to the carriage  370 B. 
     As shown in  FIG. 47 , in the toy passenger vehicle  461 , the follower wheel devices  631 ,  671  are rotatably mounted to the carriage frames  371  to form the follower-side carriages  370 C. The follower wheel device  631  of one of the pair of carriages  370 C,  370 C and the follower wheel device  631  of the other are rotatably mounted to the carriage frames  371  so that the third wheel main bodies  641  are in opposite positions (coming in contact with different rails). Lower ends of the conductive contacts  441 ,  445  come in sliding contact with the second axles  632 ,  632  of the follower wheel devices  631 ,  631  mounted to the carriages  370 C. 
     The powered toy vehicle  401  and the toy passenger vehicle  461  are coupled by a coupler. It is possible to place the drive wheel devices  601  and the follower wheel devices  631  of the powered toy vehicle  401  on the metal rails  561 ,  561  of the rail track device  501 . The pair of magnet rings  617 ,  617  of the drive wheel device  601  comes in contact with the metal rails  561 ,  561  while attracting the rails. The one magnet ring  647  of the follower wheel device  631  come in contact with the metal rail  561  while attracting the rail. A positive electrode of a power source is connected to one ( 561 A) of the metal rails  561  and a negative electrode of the power source is connected to the other ( 561 B) of the metal rails  561 . 
     An electric current flows from one ( 647 A) of the magnet rings  647  of the third wheel main bodies  641  in contact with the metal rail  561 A to the metal rail  561 B via the third wheel main body  641 , the second axle  632 , the first conductive contact  441 , the one contact terminal  455 , the positive terminal of the drive motor  416 , the negative terminal of the drive motor  416 , the other contact terminal  456 , the second conductive contact  445 , the second axle  632 , the third wheel main body  641 , and the other ( 647 B) of the magnet rings  647  of the third wheel main bodies  641 . With this electric current, the drive motor  416  rotates, the rotation is transmitted to the gears  608 ,  608  via the gear train  420 A, and the drive wheel devices  601 ,  601  rotate on the metal rails  561 ,  561 . As a result, the powered toy vehicle  401  can travel on the rail track device  501 . 
     The toy passenger vehicle  461  is coupled to the powered toy vehicle  401  as described above with the follower wheel devices  631 ,  671  of the toy passenger vehicle  461  placed on the metal rails  561 ,  561  of the rail track device  501 . The positive electrode of the power source is connected to one ( 561 A) of the metal rails  561  and the negative electrode of the power source is connected to the other ( 561 B) of the metal rails  561 . An electric current flows from one ( 647 A) of the magnet rings  647  of the third wheel main bodies  641  in contact with the metal rail  561 A to the metal rail  561 B via the third wheel main body  641 , the second axle  632 , the first conductive contact  441 , the electronic substrate  466 , the second conductive contact  445 , the second axle  632 , the third wheel main body  641 , and the other ( 647 B) of the magnet rings  647  of the third wheel main bodies  641 . With this electric current, the electric component of the electronic substrate  466  is actuated. 
     The powered toy vehicle  401  and the toy passenger vehicle  461  are extremely small and travel on the metal rails  561 ,  561  at an interval of about 3 mm. Although the powered toy vehicle  401  and the toy passenger vehicle  461  are extremely lightweight, the first wheels  610  and the second wheels  620  of the drive wheel devices  601  and the third wheels  640  of the follower wheel devices  631  in contact with the metal rails  561  are formed of members attracting with the magnetic forces. Therefore, rotation of the drive wheel devices  601  and the follower wheel devices  631  is reliably transmitted to the metal rails  561  without slips, and the vehicles travel even on an upward slope. 
     Other embodiments of the wheel devices for a toy vehicle according to the present invention and the toy vehicles mounted with the wheel devices will be described based on  FIGS. 48(   a ) to  55 .  FIGS. 48(   a ) to  48 ( c ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention, wherein  FIG. 48(   a ) is a sectional view,  FIG. 48(   b ) is a front view, and  FIG. 48(   c ) is a perspective view.  FIGS. 49(   a ) to  50 ( c ) are general views of other embodiments of the follower wheel device for a toy vehicle according to the present invention, wherein  FIGS. 49(   a ), and  50  ( a ) are sectional views,  FIGS. 49(   b ),  50 ( b ) are front views, and  FIGS. 49(   c ), and  50 ( c ) are perspective views.  FIGS. 51(   a ), and  51 ( b ) are exploded perspective views of the drive wheel devices for a toy vehicle according to the present invention mounted into a carriage, wherein  FIG. 51(   a ) is a perspective views from above and  FIG. 51(   b ) is an exploded perspective view.  FIGS. 52(   a ), and  52  ( b ) are exploded perspective views of the follower wheel devices for a toy vehicle according to the present invention mounted into a carriage, wherein  FIG. 52(   a ) is a perspective view from above and  FIG. 52(   b ) is an exploded perspective view.  FIG. 53  is an exploded perspective view of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle.  FIGS. 54(   a ) to  54 ( e ) are sectional views of the wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle, wherein  FIG. 54(   a ) is a side view of the toy vehicle,  FIG. 54(   b ) is a sectional view of the toy vehicle taken along a line A-A,  FIG. 54(   c ) is a sectional view of the toy vehicle taken along a line B-B,  FIG. 54(   d ) is a sectional view of the toy vehicle taken along a line C-C, and  FIG. 54(   e ) is a sectional view of the toy vehicle taken along a line D-D.  FIG. 55  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
     The drive wheel device, the follower wheel devices, and the toy vehicle mounted with them will be described in detail. As shown in  FIGS. 48(   a ) to  48 ( c ), the drive wheel device  701  includes a first axle  702 , a first wheel  710 , and a second wheel  720 . The first axle  702  is made of a synthetic resin material such as polyacetal (POM) and formed into a cylindrical shape. Substantially at a center and a peripheral face of the first axle  702 , a gear  708  is molded integrally. Cog tips of the gear  708  are curved to form spherical surfaces. 
     The first wheel  710  includes a first wheel main body  711  and a magnet ring  717 . The first wheel main body  711  includes a mounting shaft  719 , a first flange  712 , and a fitting shaft  713  and is integrally molded of a metal member such as a copper member. The first flange  712  is provided, at an outer side face  715  thereof, with the mounting shaft  719  substantially coaxial with the first flange  712 . The first flange  712  is attached with the fitting shaft  713  substantially coaxial with the first flange  712  at an inner side face  716  thereof. A tip end face  718  of the mounting shaft  719  is formed with a substantially conical support recessed portion  714  substantially coaxial with the first wheel main body  711 . To an outer peripheral face of the mounting shaft  719 , the magnet ring  717  is fixedly mounted to come in contact with the first flange  712 . The magnet ring  717  has a smaller outer diameter than the first flange  712 . The first wheel  710  is fixed with its fitting shaft  713  fitted into the first axle  702 . Since the second wheel  720  has the same structure as the first wheel  710 , description of the second wheel  720  will not be made here. The magnet rings  717 ,  717  function as wheels traveling on the rails  561 ,  561 . 
     As shown in  FIGS. 49(   a ) to  49 ( c ), the follower wheel device  731  includes a second axle  732 , a first wheel  710 , and a second wheel  720 . The second axle  732  is made of a synthetic resin material such as polyacetal (POM) into a cylindrical shape. The first wheel  710  and the second wheel  720  are fixed with their fitting shafts  713  fitted in the second axle  732 . Magnet rings  717 ,  717  function as wheels traveling on the rails  561 ,  561 . 
     As shown in  FIGS. 50(   a ) to  50 ( c ), the follower wheel device  751  includes a second axle  752  and a pair of fourth wheels  760 . Each of the fourth wheels  760  includes a fourth wheel main body  761 , a fourth flange  762 , and a fitting shaft  763  and is integrally molded as a metal member such as a copper member. The fourth flange  762  is provided, at an outer side face  765  thereof, with the fourth wheel main body  761  substantially coaxial with the fourth flange  762 . The fourth flange  762  is provided, at an inner side face  766  thereof, with the fitting shaft  763  substantially coaxial with the fourth flange  762 . A tip end face  768  of the fourth wheel main body  761  is formed with a substantially conical support recessed portion  764  substantially coaxial with the fourth wheel main body  761 . The fourth wheel main body  761  has substantially the same outer diameter as the magnet ring  717 . The fourth wheel  760  is fixedly mounted to the second axle  752  with the fitting shaft  763  fitted in the second axle  752  and the fourth flange  762  joined to an end face of the second axle  752 . In this way, in the follower wheel device  751 , the fourth wheels  760  are mounted to opposite sides of the second axle  752 . 
     As shown in  FIGS. 51(   a ) to  52 ( b ), the above-described drive wheel device  701  and the follower wheel device  731  are rotatably mounted to the carriage frames  771 ,  821  of the toy vehicles. The drive wheel devices  701  are mounted into the carriage frame  771  to form the carriage  770 A. The follower wheel devices  731  are mounted into the carriage frame  821  to form the carriage  770 B. 
     As shown in  FIGS. 51(   a ) and  51 ( b ), the carriage frame  771  is configured by a substantially rectangular main frame  772 , a middle member  773  for partitioning an inside of the main frame  772 , and locking lugs  775 , and the like, and is integrally molded of a synthetic resin. The main frame  772  is configured by a pair of longitudinal members  776 ,  776  in a longitudinal direction and a pair of lateral members  777 ,  777  in a lateral direction and provided at opposite ends of the longitudinal members  776 ,  776 . An outer face  778  of the lateral member  777  is formed of a convex curved face in the shape of an arc having a center substantially at a center of the main frame  772 . The outer face  778  of one of the lateral members  777  is formed, substantially at a center thereof, with a coupling hole  778 A. 
     The middle member  773  is provided to connect substantially central portions of the pair of longitudinal members  776 ,  776  and is mounted to lower faces of the longitudinal members  776 ,  776  to be in positions lower than the lateral members  777 ,  777 . The middle member  773  forms housing portions  781 ,  782  for housing the drive wheel devices  701 ,  701  in the main frame  772 . The middle member  773  is formed with a recessed step portion  774  at a middle portion to avoid contact with the final gear  430  and a pair of locking protrusions  789 ,  789  at each of opposite ends. Into a clearance between each pair of locking protrusions  789 ,  789  and an inner face of the longitudinal member  776 , a bearing plate  800  is inserted and mounted. The bearing plate  800  is formed by pressing a metal sheet such as a copper sheet. The bearing plate  800  is formed with a fitting recessed portion  801  to be fitted over the middle member  773  substantially at a center of a lower end of the plate  800 , support protruding portions  802 ,  802  at opposite sides of a front face of the plate  800 , and an L-shaped protruding chip  805  substantially at a center of an upper end of the plate  800 . The support protruding portions  802  are formed into substantially conical shapes and rotatably fitted in the support recessed portions  714  of the above-described drive wheel devices  701 . The protruding chip  805  is formed of a spring receiving portion  806  and a spring insertion portion  807  into the substantially L shape as described above. 
     In the drive wheel device  701 , the support protruding portion  802  of one of the bearing plates  800  is rotatably inserted into one of the support recessed portions  714  and the support protruding portion  802  of the other bearing plate  800  is rotatably inserted into the other support recessed portion  714 . In this way, with the pair of drive wheel devices  701 ,  701  sandwiched between the pair of bearing plates  800 ,  800 , the pair of bearing plates  800 ,  800  are inserted into the clearances between the pairs of locking protrusions  789 ,  789  and the inner faces of the longitudinal members  776 . As a result, the drive wheel devices  701 ,  701  are rotatably mounted to the carriage frame  771 . In other words, the drive wheel devices  701  are rotatably mounted to the carriage frame  771  with their support recessed portions  714 ,  714  rotatably supported by the support protruding portions  802 ,  802  of the pair of bearing plates  800 ,  800  mounted to the carriage frame  771 . When the bearing plate  800  is inserted into the clearance between the pair of locking protrusions  789 ,  789  and the inner face of the longitudinal member  776 , the fitting recessed portion  801  is fitted over the middle member  773  and therefore the bearing plate  800  is positioned and retained stably. Respective devices of the pair of drive wheel devices  701 ,  701  are housed respectively in the housing portion  781  and the housing portion  782  of the carriage frame  771 . The lateral members  777 ,  777  are formed, substantially at centers of upper faces  777 B,  777 B thereof, with the locking lugs  775 ,  775 . 
     As shown in  FIGS. 52(   a ), and  52 ( b ), the carriage frame  821  is configured by a substantially rectangular main frame  822 , a middle member  823  for partitioning an inside of the main frame  822 , and locking lugs  825  . . . and is integrally molded of a synthetic resin. The main frame  822  is configured by a pair of longitudinal members  826 ,  826  in a longitudinal direction and a pair of lateral members  827 ,  827  in a lateral direction and provided at opposite ends of the longitudinal members  826 ,  826 . An outer face  828  of the lateral member  827  is formed of a convex curved face in the shape of an arc having a center substantially at a center of the main frame  822 . The outer face  828  of one of the lateral members  827  is formed, substantially at a center thereof, with a coupling hole  828 A. 
     The middle member  823  is provided to connect substantially central portions of the pair of longitudinal members  826 ,  826  and is mounted to lower faces of the longitudinal members  826 ,  826  to be in positions lower than the lateral members  827 ,  827 . The middle member  823  forms housing portions  831 ,  832  for housing the follower wheel devices  731 ,  731  in the main frame  822 . The middle member  823  is formed, on an upper face thereof, with a pair of fitting protrusions  841 ,  841 . The upper face of the middle member  823  is mounted with a fixing member  835 . The fixing member  835  is formed in the shape of a rectangular parallelepiped, formed with fitting holes  836 ,  836  to be fitted over the fitting protrusions  841 ,  841  of the middle member  823 , and formed to project, at a center of an upper face thereof, with a center shaft  837 . The fixing member  835  is fixedly mounted to the middle member  823  when their fitting holes  836 ,  836  are fitted over the fitting protrusions  841 ,  841  of the middle member  823 . When the fixing member  835  is mounted to the middle member  823 , clearances are formed between the fixing member  835  and inner faces of the longitudinal members  826 ,  826 . Into the clearances, the bearing plates  800  are inserted and mounted. 
     In the follower wheel device  731 , the support protruding portion  802  of one of the bearing plates  800  is rotatably inserted into one of the support recessed portions  714  and the support protruding portion  802  of the other bearing plate  800  is rotatably inserted into the other support recessed portion  714 . In this way, with the pair of follower wheel devices  731 ,  731  sandwiched between the pair of bearing plates  800 ,  800 , the pair of bearing plates  800 ,  800  are inserted into the clearances between the fixing member  835  and the inner faces of the longitudinal members  776 . As a result, the follower wheel devices  731 ,  731  are rotatably mounted to the carriage frame  821 . In other words, the follower wheel devices  731  are rotatably mounted to the carriage frame  821  with their support recessed portions  714 ,  714  rotatably supported by the support protruding portions  802 ,  802  of the pair of bearing plates  800 ,  800  mounted to the carriage frame  821 . When the bearing plate  800  is inserted into the clearance between the fixing member  835  and the inner face of the longitudinal member  776 , the fitting recessed portion  801  is fitted over the middle member  823  and therefore the bearing plate  800  is positioned and retained stably. Respective devices of the pair of follower wheel devices  731 ,  731  are housed respectively in the housing portion  831  and the housing portion  832  of the carriage frame  821 . The lateral members  827 ,  827  are formed, substantially at centers of upper faces  827 B,  827 B thereof, with the locking lugs  825 ,  825 . 
     As shown in  FIG. 53 , a toy vehicle main body  852  of a powered toy vehicle  851  includes a chassis  853  and a vehicle body  855  mounted to the chassis  853 . Formed at each of a front portion and a rear portion of the chassis  853  is a pair of curved locking grooves  860 ,  860  which are opposed to each other and to which the carriage frames  771 ,  821  can be mounted. 
     The drive-side carriage  770 A is mounted to the chassis  853  by locking the locking lugs  775 ,  775  of the carriage frame  771  in the locking grooves  860 ,  860 . The follower-side carriage  770 B is mounted to the chassis  853  by locking the locking lugs  825 ,  825  of the carriage frame  821  in the locking grooves  860 ,  860 . The carriage  770 B can rotate about the center shaft  837 , because the center shaft  837  formed on the upper face of the fixing member  835  is pivoted in a bearing hole formed in the lower face of the chassis  853 . 
     The chassis  853  is provided with the drive motor  416  and the above-described gear train  420 A. The chassis  853  is mounted with a gear box  856  in which the above-described gear train  420 A is rotatably mounted. The final gear  430  is adapted to be placed above the pair of gears  708 ,  708  of the carriage  770 A mounted to the chassis  853 . The chassis  853  is formed with an opening  854  for allowing the final gear  430  to protrude from the lower face of the chassis  853  and the final gear  430  protruding through the opening  854  is engaged with the gears  708 ,  708  of the drive wheel devices  701 ,  701  mounted to the carriage  770 A. 
     The chassis  853  is provided with the conductive contacts  441 ,  445  positioned above the bearing plates  800 ,  800  of the carriage  770 A. The conductive contacts  441 ,  445  are spring members made of conductive metal. The conductive contacts  441 ,  445  are guided by substantially angular U-shaped guide grooves  845 ,  845  formed on opposite sides of the gear box  856  and substantially angular U-shaped guide recessed portions  857 ,  857  formed on opposite sides of the chassis  853 . Upper ends of the conductive contacts  441 ,  445  come in contact with conductive contact plates  847 ,  848 . Lower ends of the conductive contacts  441 ,  445  are pressed against the spring receiving portions  806 ,  806  with the spring insertion portions  807 ,  807  of the bearing plates  800 ,  800  inserted into lower portions of the conductive contacts  441 ,  445 . The conductive contact terminals  441 ,  445  prevent the bearing plates  800 ,  800  from coming off the carriage frame  771  and also function as suspensions of the drive wheel device  701 . 
     The chassis  853  is provided with the conductive contacts  441 ,  445  positioned above the bearing plates  800 ,  800  of the carriage  770 B. The conductive contacts  441 ,  445  are spring members made of conductive metal. The conductive contacts  441 ,  445  are guided by substantially angular U-shaped guide grooves  843 ,  843  formed on opposite sides of the guide member  842  formed at an upper portion of the chassis  853 . Upper ends of the conductive contacts  441 ,  445  come in contact with conductive contact plates  847 ,  848 . Lower ends of the conductive contacts  441 ,  445  are pressed against the spring receiving portions  806 ,  806  with the spring insertion portions  807 ,  807  of the bearing plates  800 ,  800  inserted into lower portions of the conductive contacts  441 ,  445 . The conductive contact terminals  441 ,  445  prevent the bearing plates  800 ,  800  from coming off the carriage frame  821  and also function as suspensions of the drive wheel device  731 . 
     Inside the vehicle body  855 , the conductive contact plates  847 ,  848  are fixedly mounted. The conductive contact plate  847  is electrically connected to the upper end of the conductive contact  441  positioned above the carriage  770 A, the positive terminal of the drive motor  416 , and the upper end of the conductive contact  441  positioned above the carriage  770 B when the vehicle body  855  is mounted to the chassis  853 . Similarly, the conductive contact plate  848  is electrically connected to the upper end of the conductive contact  445  positioned above the carriage  770 A, the negative terminal of the drive motor  416 , and the upper end of the conductive contact  445  positioned above the carriage  770 B when the vehicle body  855  is mounted to the chassis  853 . 
     The above-described follower wheel devices  731  and the follower wheel devices  751  are rotatably mounted to a carriage frame  371  and a carriage frame  821  of a toy passenger vehicle  861  as shown in  FIG. 55 . The follower wheel devices  731 ,  751  are mounted into the carriage frame  371  to form a carriage  770 C. The follower wheel devices  731 ,  751  are mounted into the carriage frame  821  to form a carriage  770 D. 
     A toy vehicle main body  862  of the toy passenger vehicle  861  includes a chassis  863  and a vehicle body  865  mounted to the chassis  863 . Formed at each of a front portion and a rear portion of the chassis  863  is a pair of curved locking grooves  868 ,  868  which are facing each other and to which the carriage frames  371 ,  821  can be mounted. The carriage  770 D is mounted to the chassis  863  by locking the locking lugs  825 ,  825  of the carriage frame  821  in the locking grooves  868 ,  868 . The carriage  770 D is mounted to the chassis  863  by locking the locking lugs  825 ,  825  of the carriage frame  821  to the locking grooves  868 ,  868 . The carriage  770 D can rotate about the center shaft  837 , because the center shaft  837  formed on the upper face of the fixing member  835  is pivoted in the bearing hole formed in the lower face of the chassis  863 . The carriage  770 C is mounted to the chassis  863  by locking the locking lugs  393 ,  393  of the carriage frame  371  to the locking grooves  868 ,  868 . 
     The chassis  863  is provided with the conductive contacts  441 ,  445  positioned above the bearing plates  800 ,  800  of the carriage  770 D. The conductive contacts  441 ,  445  are spring members made of conductive metal. The conductive contacts  441 ,  445  are guided by substantially angular U-shaped guide grooves  871 ,  871  formed on opposite sides of a guide member  870  formed on an upper portion of the chassis  863 . Upper ends of the conductive contacts  441 ,  445  come in contact with conductive contact plates  872 ,  873 . Lower ends of the conductive contacts  441 ,  445  are pressed against the spring receiving portions  806 ,  806  with the spring insertion portions  807 ,  807  of the bearing plates  800 ,  800  inserted into lower portions of the conductive contacts  441 ,  445 . The conductive contact terminals  441 ,  445  prevent the bearing plates  800 ,  800  from coming off the carriage frame  821  and also function as suspensions of the follower wheel device  731 . 
     Inside the vehicle body  865 , the conductive contact plates  872 ,  873  are fixedly mounted. The conductive contact plate  872  is electrically connected to the upper end of the conductive contact  441  positioned above the carriage  770 D when the vehicle body  865  is mounted to the chassis  863 . Similarly, the conductive contact plate  873  is electrically connected to the upper end of the conductive contact  445  positioned above the carriage  770 D when the vehicle body  855  is mounted to the chassis  853 . The conductive contact plates  872 ,  873  are electrically connected to the electric component  875  such as an LED provided in the vehicle body  865 . 
     The powered toy vehicle  851  and the toy passenger vehicle  861  are coupled by a coupler. It is possible to place the drive wheel devices  701  and the follower wheel devices  731  of the powered toy vehicle  851  on the metal rails  561 ,  561  of the rail track device  501 . The pairs of magnet rings  717 ,  717  of the drive wheel devices  701  come in contact with the metal rails  561 ,  561  while attracting the rails. The pairs of magnet rings  717  of the follower wheel devices  731  come in contact with the metal rails  561 ,  561  while attracting the rails. In this manner, all the wheels of the powered toy vehicle  851  to which power is transmitted attract the metal rails  561 ,  561  with magnetic forces. Therefore, all the wheels do not slip on the pair of metal rails  561 ,  561 . As s result, power of the drive motor  416  can be reliably transmitted to the pair of metal rails  561 ,  561 . 
     A positive electrode of a power source is connected to one ( 561 A) of the metal rails  561  and a negative electrode of the power source is connected to the other ( 561 B) of the metal rails  561 . An electric current flows from the magnet rings  717 ,  717  ( 717 A) of the first wheel main bodies  711 ,  711  of the carriage  770 A in contact with the metal rail  561 A to the metal rail  561 B via the first wheel main bodies  711 ,  711 , the bearing plate  800 , the first conductive contact  441 , one  847  of the contact terminals, the positive terminal of the drive motor  416 , the negative terminal of the drive motor  416 , the other contact terminal  848 , the second conductive contact  445 , the bearing plate  800 , the first wheel main bodies  711 ,  711 , and the magnet rings  717 ,  717  ( 717 B) of the first wheel main bodies  711 ,  711 . With this electric current, the drive motor  416  rotates, the rotation is transmitted to the gears  708 ,  708  via the gear train  420 A, and the drive wheel devices  701 ,  701  rotate on the metal rails  561 ,  561 . As a result, the powered toy vehicle  851  can travel on the rail track device  501 . 
     An electric current flows from the magnet rings  717 ,  717  ( 717 A) of the first wheel main bodies  711 ,  711  of the carriage  770 B in contact with the metal rail  561 A to the metal rail  561 B via the first wheel main bodies  711 ,  711 , the bearing plate  800 , the first conductive contact  441 , one  847  of the contact terminals, the positive terminal of the drive motor  416 , the negative terminal of the drive motor  416 , the other contact terminal  848 , the second conductive contact  445 , the bearing plate  800 , the first wheel main bodies  711 ,  711 , and the magnet rings  717 ,  717  ( 717 B) of the first wheel main bodies  711 ,  711 . With this electric current, the drive motor  416  rotates, the rotation is transmitted to the gears  708 ,  708  via the gear train  420 A, and the drive wheel devices  701 ,  701  rotate on the metal rails  561 ,  561 . As a result, the powered toy vehicle  851  can travel on the rail track device  501 . In other words, the powered toy vehicle  851  can be powered from both the carriage  770 A and carriage  770 B. Especially, the powered toy vehicle  851  can be powered from any of the four magnet rings  717 ,  717  in contact with the metal rails  561  and therefore it is possible to reliably drive the drive motor  416  without interruption. 
     The toy passenger vehicle  861  is coupled to the powered toy vehicle  851  as described above with the follower wheel devices  731 ,  751  of the toy passenger vehicle  861  placed on the metal rails  561 ,  561  of the rail track device  501 . The positive electrode of the power source is connected to one ( 561 A) of the metal rails  561  and the negative electrode of the power source is connected to the other ( 561 B) of the metal rails  561 . An electric current flows from the magnet ring  717  ( 717 A) of the first wheel main body  711  in contact with the metal rail  561 A and the fourth wheel main body  761  ( 761 A) to the metal rail  561 B via the bearing plate  800 , the first conductive contact  441 , the conductive contact plate  872 , the electric component  875 , the conductive contact plate  873 , the second conductive contact  445 , the bearing plate  800 , the magnet ring  717  ( 717 B) of the first wheel main body  711 , and the fourth wheel main body  761  ( 761 B). With this electric current, the electric component  875  is actuated. 
     The powered toy vehicle  851  and the toy passenger vehicle  861  are extremely small and travel on the metal rails  561 ,  561  at an interval of about 3 mm. Although the powered toy vehicle  851  and the toy passenger vehicle  861  are extremely lightweight, the wheels of the drive wheel devices  701  and the follower wheel devices  731  in contact with the metal rails  561  are formed of magnets. Therefore, rotation of the drive wheel devices  701  and the follower wheel devices  731  is reliably transmitted to the metal rails  561  without slips and the vehicles travel even on an upward slope. 
     INDUSTRIAL APPLICABILITY 
     The wheel device for a toy vehicle and the toy vehicle according to the invention can be used for a toy train that travels on a pair of metal rails. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1(   a ) to  1 ( c ) are general views of embodiments of a drive wheel device for a toy vehicle according to the present invention. 
       FIGS. 2(   a ) and  2 ( b ) are exploded perspective views of the drive wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIG. 3  is an exploded perspective view of the drive wheel devices and follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 4(   a ) and  4 ( b ) are sectional views of the wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 5(   a ) and  5 ( b ) are perspective assembly drawings of  FIG. 4 . 
       FIG. 6  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIG. 7  is a perspective assembly drawing of  FIG. 6 . 
       FIG. 8  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIG. 9  is a perspective assembly drawing of  FIG. 8 . 
       FIG. 10  is a perspective view of an embodiment of a rail track device according to the present invention. 
       FIG. 11  is an exploded perspective view of  FIG. 10 . 
       FIGS. 12(   a ) to  12 ( d ) are explanatory views of the rail track device. 
       FIGS. 13(   a ) to  13 ( c ) are explanatory views of the rail track device from which a bottom plate is detached and which is viewed from below. 
       FIGS. 14(   a ) and  14 ( b ) are explanatory views for explaining a relationship between a rail track belt and metal rails. 
       FIGS. 15(   a ) to  15 ( e ) are explanatory views showing a method of connecting the rail track devices. 
       FIG. 16  is a plan view showing a relationship between the metal rails and the wheel devices. 
       FIGS. 17(   a ) and  17 ( b ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention. 
       FIGS. 18(   a ) and  18 ( b ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 19(   a ) and  19 ( b ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 20(   a ) and  20 ( b ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 21(   a ) and  21 ( b ) are exploded perspective views of the drive wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIGS. 22(   a ) and  22 ( b ) are exploded perspective views of the follower wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIGS. 23(   a ) and  23 ( b ) are exploded perspective views of the follower wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIGS. 24(   a ) and  24 ( b ) are exploded perspective views of the follower wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIG. 25  is an exploded perspective view of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 26(   a ) and  26 ( b ) are sectional views of the wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 27(   a ) and  27 ( b ) are assembly drawings of  FIG. 25 . 
       FIG. 28  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 29(   a ) and  29 ( b ) are assembly drawings of  FIG. 28 . 
       FIG. 30  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 31(   a ) and  31 ( b ) are assembly drawings of  FIG. 30 . 
       FIGS. 32(   a ) and  32 ( b ) are perspective views of a coupler. 
       FIGS. 33(   a ) to  33 ( c ) are explanatory views of toy vehicles coupled by the couplers. 
       FIG. 34  is a perspective view of another embodiment of the rail track device according to the present invention. 
       FIG. 35  is an exploded perspective view of  FIG. 34 . 
       FIGS. 36(   a ) and  36 ( b ) are explanatory views of the rail track device. 
       FIGS. 37(   a ) to  37 ( c ) are explanatory views of the rail track device. 
       FIGS. 38(   a ) to  38 ( c ) are explanatory views of the rail track device from which a bottom plate is detached and which is viewed from below. 
       FIG. 39  is an explanatory view for explaining a relationship between a rail track belt and metal rails. 
       FIGS. 40(   a ) and  40 ( b ) are explanatory views of the metal rail. 
       FIGS. 41(   a ) and  41 ( b ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention. 
       FIGS. 42(   a ) and  42 ( b ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 43(   a ) to  43 ( c ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention. 
       FIGS. 44(   a ) to  44 ( c ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 45(   a ) to  45 ( c ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIG. 46  is an exploded perspective view of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIG. 47  is an exploded perspective view of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 48(   a ) to  48 ( c ) are general views of another embodiment of the drive wheel device for a toy vehicle according to the present invention. 
       FIGS. 49(   a ) to  49 ( c ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 50(   a ) to  50 ( c ) are general views of another embodiment of the follower wheel device for a toy vehicle according to the present invention. 
       FIGS. 51(   a ) and  51 ( b ) are exploded perspective views of the drive wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIGS. 52(   a ) and  52 ( b ) are exploded perspective views of the follower wheel devices for a toy vehicle according to the present invention mounted into a carriage. 
       FIG. 53  is an exploded perspective view of the drive wheel devices and the follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIGS. 54(   a ) to  54 ( e ) are sectional views of the wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
       FIG. 55  is an exploded perspective view of other follower wheel devices for a toy vehicle according to the present invention mounted into a toy vehicle. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                  1 
                 drive wheel device 
               
               
                   
                  1A 
                 drive wheel device 
               
               
                   
                  2 
                 first axle 
               
               
                   
                  3 
                 one side face 
               
               
                   
                  5 
                 first round shaft recessed portion 
               
               
                   
                  6 
                 the other side face 
               
               
                   
                  7 
                 second round shaft recessed portion 
               
               
                   
                  8 
                 gear 
               
               
                   
                  10 
                 first wheel 
               
               
                   
                  11 
                 first wheel main body 
               
               
                   
                  12 
                 first flange 
               
               
                   
                  13 
                 fitting shaft 
               
               
                   
                  15 
                 outer side face 
               
               
                   
                  16 
                 inner side face 
               
               
                   
                  20 
                 second wheel 
               
               
                   
                  21 
                 second wheel main body 
               
               
                   
                  22 
                 second flange 
               
               
                   
                  23 
                 boss portion 
               
               
                   
                  25 
                 outer side face 
               
               
                   
                  26 
                 inner side face 
               
               
                   
                  27 
                 through hole 
               
               
                   
                  29 
                 protruding portion 
               
               
                   
                  31 
                 follower wheel device 
               
               
                   
                  32 
                 second axle 
               
               
                   
                  39 
                 protruding portion 
               
               
                   
                  40 
                 third wheel 
               
               
                   
                  41 
                 third wheel main body 
               
               
                   
                  42 
                 third flange 
               
               
                   
                  43 
                 boss portion 
               
               
                   
                  45 
                 outer side face 
               
               
                   
                  46 
                 inner side face 
               
               
                   
                  47 
                 fitting hole 
               
               
                   
                  50 
                 fourth wheel 
               
               
                   
                  51 
                 fourth wheel main body 
               
               
                   
                  52 
                 fourth flange 
               
               
                   
                  53 
                 boss portion 
               
               
                   
                  55 
                 outer side face 
               
               
                   
                  56 
                 inner side face 
               
               
                   
                  57 
                 through hole 
               
               
                   
                  60 
                 conductive ring 
               
               
                   
                  65 
                 follower wheel device 
               
               
                   
                  66 
                 axle 
               
               
                   
                  67 
                 a pair of wheels 
               
               
                   
                  68 
                 wheel main body 
               
               
                   
                  69 
                 flange 
               
               
                   
                  70 
                 carriage 
               
               
                   
                  70A 
                 carriage 
               
               
                   
                  70B 
                 carriage 
               
               
                   
                  70C 
                 carriage 
               
               
                   
                  71 
                 carriage frame 
               
               
                   
                  72 
                 main frame 
               
               
                   
                  73 
                 middle member 
               
               
                   
                  74 
                 inner face 
               
               
                   
                  75 
                 bearing member 
               
               
                   
                  76 
                 longitudinal member 
               
               
                   
                  77 
                 lateral member 
               
               
                   
                  77a 
                 lower face 
               
               
                   
                  78 
                 outer face 
               
               
                   
                  79 
                 inner face 
               
               
                   
                  81 
                 housing portion 
               
               
                   
                  82 
                 housing portion 
               
               
                   
                  85 
                 guide groove 
               
               
                   
                  90 
                 shaft retaining member 
               
               
                   
                  91 
                 guide protrusion 
               
               
                   
                  92 
                 shaft retaining protrusion 
               
               
                   
                 101 
                 powered toy vehicle 
               
               
                   
                 102 
                 toy vehicle main body 
               
               
                   
                 103 
                 chassis 
               
               
                   
                 105 
                 vehicle body 
               
               
                   
                 106 
                 lower face 
               
               
                   
                 110 
                 locking member 
               
               
                   
                 111 
                 sliding contact face 
               
               
                   
                 113 
                 engaging protruding portions 
               
               
                   
                 116 
                 drive motor 
               
               
                   
                 120 
                 gear train 
               
               
                   
                 121 
                 drive gear 
               
               
                   
                 122 
                 crown gear 
               
               
                   
                 123 
                 small gear 
               
               
                   
                 125 
                 large gear 
               
               
                   
                 126 
                 small gear 
               
               
                   
                 127 
                 large gear 
               
               
                   
                 128 
                 small gear 
               
               
                   
                 129 
                 large gear 
               
               
                   
                 130 
                 final gear 
               
               
                   
                 131 
                 gear box 
               
               
                   
                 133 
                 opening 
               
               
                   
                 141 
                 first conductive contact 
               
               
                   
                 142 
                 guide chip 
               
               
                   
                 143 
                 spring receiving protruding chip 
               
               
                   
                 145 
                 second conductive contact 
               
               
                   
                 151 
                 guide member 
               
               
                   
                 152 
                 guide groove 
               
               
                   
                 155 
                 spring 
               
               
                   
                 156 
                 spring retaining chip 
               
               
                   
                 157 
                 guide protrusion 
               
               
                   
                 158 
                 opening 
               
               
                   
                 159 
                 protrusion 
               
               
                   
                 161 
                 toy passenger vehicle 
               
               
                   
                 162 
                 toy vehicle main body 
               
               
                   
                 163 
                 chassis 
               
               
                   
                 165 
                 vehicle body 
               
               
                   
                 166 
                 lower face 
               
               
                   
                 167 
                 protrusion 
               
               
                   
                 168 
                 opening 
               
               
                   
                 171 
                 toy passenger vehicle 
               
               
                   
                 172 
                 toy vehicle main body 
               
               
                   
                 201 
                 rail track device 
               
               
                   
                 202 
                 rail track belt 
               
               
                   
                 203 
                 upper face plate 
               
               
                   
                 205 
                 right slope plate 
               
               
                   
                 206 
                 left slope plate 
               
               
                   
                 207 
                 right side plate 
               
               
                   
                 208 
                 left side plate 
               
               
                   
                 210 
                 front face plate 
               
               
                   
                 211 
                 rear face plate 
               
               
                   
                 213 
                 protrusion 
               
               
                   
                 215 
                 groove 
               
               
                   
                 216 
                 groove 
               
               
                   
                 218 
                 side face 
               
               
                   
                 219 
                 bottom face 
               
               
                   
                 221 
                 insertion hole 
               
               
                   
                 222 
                 insertion hole 
               
               
                   
                 223 
                 insertion hole 
               
               
                   
                 224 
                 insertion hole 
               
               
                   
                 226 
                 back face 
               
               
                   
                 230 
                 magnet housing frame (mounting portion) 
               
               
                   
                 231 
                 magnet housing frame (mounting portion) 
               
               
                   
                 232 
                 insertion groove 
               
               
                   
                 233 
                 insertion groove 
               
               
                   
                 235 
                 insertion groove 
               
               
                   
                 236 
                 insertion groove 
               
               
                   
                 240 
                 boss 
               
               
                   
                 241 
                 internal thread portion 
               
               
                   
                 242 
                 positioning hole 
               
               
                   
                 243 
                 boss 
               
               
                   
                 245 
                 bottom plate 
               
               
                   
                 246 
                 fitting pin 
               
               
                   
                 247 
                 through hole 
               
               
                   
                 248 
                 screw 
               
               
                   
                 250 
                 magnet 
               
               
                   
                 261 
                 metal rail 
               
               
                   
                 262 
                 contact face 
               
               
                   
                 263 
                 front insertion chip 
               
               
                   
                 265 
                 first middle insertion chip 
               
               
                   
                 266 
                 second middle insertion chip 
               
               
                   
                 267 
                 rear insertion chip 
               
               
                   
                 271 
                 contact chip 
               
               
                   
                 272 
                 insertion recessed portion 
               
               
                   
                 273 
                 contact chip 
               
               
                   
                 275 
                 locking lug 
               
               
                   
                 276 
                 contact chip 
               
               
                   
                 278 
                 locking lug 
               
               
                   
                 279 
                 locking lug 
               
               
                   
                 280 
                 contact chip 
               
               
                   
                 281 
                 insertion protruding portion 
               
               
                   
                 282 
                 locking lug 
               
               
                   
                 290 
                 insertion hole 
               
               
                   
                 301 
                 drive wheel device 
               
               
                   
                 301A 
                 wheel device (follower wheel device) 
               
               
                   
                 302 
                 first axle 
               
               
                   
                 303 
                 one side face 
               
               
                   
                 305 
                 first round shaft recessed portion 
               
               
                   
                 306 
                 the other side face 
               
               
                   
                 307 
                 second round shaft recessed portion 
               
               
                   
                 307A 
                 round shaft recessed portion 
               
               
                   
                 308 
                 gear 
               
               
                   
                 310 
                 first wheel 
               
               
                   
                 311 
                 first wheel main body 
               
               
                   
                 312 
                 first flange 
               
               
                   
                 313 
                 fitting shaft 
               
               
                   
                 314 
                 support recessed portion 
               
               
                   
                 315 
                 outer side face 
               
               
                   
                 316 
                 inner side face 
               
               
                   
                 318 
                 tip end face 
               
               
                   
                 320 
                 second wheel 
               
               
                   
                 320A 
                 second wheel 
               
               
                   
                 321 
                 second wheel main body 
               
               
                   
                 322 
                 second flange 
               
               
                   
                 323 
                 boss portion 
               
               
                   
                 324 
                 support recessed portion 
               
               
                   
                 324a 
                 tip end face 
               
               
                   
                 325 
                 outer side face 
               
               
                   
                 326 
                 inner side face 
               
               
                   
                 327 
                 through hole 
               
               
                   
                 328 
                 magnet 
               
               
                   
                 328A 
                 magnet 
               
               
                   
                 329 
                 protruding portion 
               
               
                   
                 330 
                 rolling shaft 
               
               
                   
                 330A 
                 rolling shaft 
               
               
                   
                 331 
                 follower wheel device 
               
               
                   
                 332 
                 second axle 
               
               
                   
                 333 
                 housing recessed portion 
               
               
                   
                 333A 
                 housing recessed portion 
               
               
                   
                 334 
                 support hole 
               
               
                   
                 334A 
                 support hole 
               
               
                   
                 335 
                 one end face 
               
               
                   
                 335A 
                 one end face 
               
               
                   
                 336 
                 the other end face 
               
               
                   
                 336A 
                 the other end face 
               
               
                   
                 337 
                 opening 
               
               
                   
                 337A 
                 opening 
               
               
                   
                 340 
                 third wheel 
               
               
                   
                 341 
                 third wheel main body 
               
               
                   
                 342 
                 third flange 
               
               
                   
                 343 
                 boss portion 
               
               
                   
                 344 
                 support recessed portion 
               
               
                   
                 345 
                 outer side face 
               
               
                   
                 346 
                 inner side face 
               
               
                   
                 347 
                 fitting hole 
               
               
                   
                 348 
                 tip end face 
               
               
                   
                 350 
                 fourth wheel 
               
               
                   
                 351 
                 fourth wheel main body 
               
               
                   
                 351A 
                 fourth wheel main body 
               
               
                   
                 351B 
                 fourth wheel main body 
               
               
                   
                 351C 
                 fourth wheel main body 
               
               
                   
                 351D 
                 fourth wheel main body 
               
               
                   
                 352 
                 fourth flange 
               
               
                   
                 353 
                 boss portion 
               
               
                   
                 354 
                 support recessed portion 
               
               
                   
                 354a 
                 tip end face 
               
               
                   
                 355 
                 outer side face 
               
               
                   
                 356 
                 inner side face 
               
               
                   
                 357 
                 through hole 
               
               
                   
                 360 
                 conductive ring 
               
               
                   
                 364 
                 support recessed portion 
               
               
                   
                 365 
                 follower wheel device 
               
               
                   
                 366 
                 axle 
               
               
                   
                 367 
                 wheel 
               
               
                   
                 368 
                 wheel main body 
               
               
                   
                 369 
                 flange 
               
               
                   
                 370A 
                 carriage 
               
               
                   
                 370B 
                 carriage 
               
               
                   
                 370C 
                 carriage 
               
               
                   
                 370D 
                 carriage 
               
               
                   
                 371 
                 carriage frame 
               
               
                   
                 372 
                 main frame 
               
               
                   
                 373 
                 middle member 
               
               
                   
                 376 
                 longitudinal member 
               
               
                   
                 376A 
                 lower face 
               
               
                   
                 376B 
                 upper face 
               
               
                   
                 377 
                 lateral member 
               
               
                   
                 377B 
                 upper face 
               
               
                   
                 378 
                 outer face 
               
               
                   
                 378A 
                 coupling hole 
               
               
                   
                 381 
                 housing portion 
               
               
                   
                 382 
                 housing portion 
               
               
                   
                 385 
                 support shaft 
               
               
                   
                 386 
                 support chip 
               
               
                   
                 387 
                 support chip 
               
               
                   
                 393 
                 locking lug 
               
               
                   
                 395 
                 guide protrusion 
               
               
                   
                 401 
                 powered toy vehicle 
               
               
                   
                 402 
                 toy vehicle main body 
               
               
                   
                 403 
                 chassis 
               
               
                   
                 405 
                 vehicle body 
               
               
                   
                 410 
                 locking groove 
               
               
                   
                 408 
                 guide groove 
               
               
                   
                 416 
                 drive motor (electric component) 
               
               
                   
                 420 
                 gear train 
               
               
                   
                 420A 
                 gear train 
               
               
                   
                 421 
                 drive gear 
               
               
                   
                 422 
                 crown gear 
               
               
                   
                 423 
                 small gear 
               
               
                   
                 425 
                 large gear 
               
               
                   
                 426 
                 small gear 
               
               
                   
                 427 
                 large gear 
               
               
                   
                 428 
                 small gear 
               
               
                   
                 429 
                 large gear 
               
               
                   
                 430 
                 final gear 
               
               
                   
                 431 
                 gear box 
               
               
                   
                 431A 
                 gear box 
               
               
                   
                 433 
                 opening 
               
               
                   
                 441 
                 conductive contact 
               
               
                   
                 445 
                 conductive contact 
               
               
                   
                 451 
                 guide member 
               
               
                   
                 454 
                 opening 
               
               
                   
                 455 
                 contact terminal 
               
               
                   
                 456 
                 contact terminal 
               
               
                   
                 457 
                 through hole 
               
               
                   
                 458 
                 through hole 
               
               
                   
                 459 
                 protrusion 
               
               
                   
                 461 
                 toy passenger vehicle 
               
               
                   
                 462 
                 toy vehicle main body 
               
               
                   
                 463 
                 chassis 
               
               
                   
                 465 
                 vehicle body 
               
               
                   
                 466 
                 electronic substrate (electric component) 
               
               
                   
                 471 
                 toy passenger vehicle 
               
               
                   
                 472 
                 toy vehicle main body 
               
               
                   
                 473 
                 chassis 
               
               
                   
                 481 
                 coupler 
               
               
                   
                 482 
                 coupling shaft 
               
               
                   
                 483 
                 design member 
               
               
                   
                 484 
                 one 
               
               
                   
                 485 
                 the other 
               
               
                   
                 501 
                 rail track device 
               
               
                   
                 502 
                 rail track belt 
               
               
                   
                 503 
                 upper face plate 
               
               
                   
                 505 
                 right slope plate 
               
               
                   
                 506 
                 left slope plate 
               
               
                   
                 507 
                 right side plate 
               
               
                   
                 508 
                 left side plate 
               
               
                   
                 510 
                 front face plate 
               
               
                   
                 511 
                 rear face plate 
               
               
                   
                 513 
                 protrusion 
               
               
                   
                 515 
                 groove 
               
               
                   
                 516 
                 groove 
               
               
                   
                 518 
                 side face 
               
               
                   
                 519 
                 bottom face 
               
               
                   
                 521 
                 insertion hole 
               
               
                   
                 522 
                 insertion hole 
               
               
                   
                 523 
                 insertion hole 
               
               
                   
                 524 
                 insertion hole 
               
               
                   
                 526 
                 back face 
               
               
                   
                 527 
                 guide protrusion 
               
               
                   
                 528 
                 guide protrusion 
               
               
                   
                 530 
                 magnet housing frame 
               
               
                   
                 531 
                 magnet housing frame 
               
               
                   
                 532 
                 insertion groove 
               
               
                   
                 535 
                 insertion groove 
               
               
                   
                 541 
                 internal thread portion 
               
               
                   
                 540 
                 boss 
               
               
                   
                 542 
                 positioning hole 
               
               
                   
                 543 
                 boss 
               
               
                   
                 545 
                 bottom plate 
               
               
                   
                 545a 
                 recessed step portion 
               
               
                   
                 545b 
                 fitting hole 
               
               
                   
                 546 
                 fitting pin 
               
               
                   
                 547 
                 through hole 
               
               
                   
                 550 
                 magnet 
               
               
                   
                 561 
                 metal rail 
               
               
                   
                 562 
                 contact face 
               
               
                   
                 563 
                 front insertion chip 
               
               
                   
                 565 
                 first middle insertion chip 
               
               
                   
                 566 
                 second middle insertion chip 
               
               
                   
                 567 
                 rear insertion chip 
               
               
                   
                 571 
                 locking lug 
               
               
                   
                 572 
                 insertion recessed portion 
               
               
                   
                 574 
                 locking lug 
               
               
                   
                 575 
                 locking lug 
               
               
                   
                 576 
                 locking lug 
               
               
                   
                 578 
                 locking lug 
               
               
                   
                 579 
                 locking lug 
               
               
                   
                 581 
                 insertion protruding portion 
               
               
                   
                 590 
                 insertion hole 
               
               
                   
                 601 
                 drive wheel device 
               
               
                   
                 602 
                 first axle 
               
               
                   
                 605 
                 cylindrical member 
               
               
                   
                 608 
                 gear 
               
               
                   
                 610 
                 first wheel 
               
               
                   
                 611 
                 first wheel main body 
               
               
                   
                 612 
                 first flange 
               
               
                   
                 613 
                 fitting shaft 
               
               
                   
                 614 
                 support recessed portion 
               
               
                   
                 615 
                 outer side face 
               
               
                   
                 616 
                 inner side face 
               
               
                   
                 617 
                 magnet ring 
               
               
                   
                 618 
                 tip end face 
               
               
                   
                 619 
                 mounting shaft 
               
               
                   
                 620 
                 second wheel 
               
               
                   
                 631 
                 follower wheel device 
               
               
                   
                 632 
                 second axle 
               
               
                   
                 640 
                 third wheel 
               
               
                   
                 641 
                 third wheel main body 
               
               
                   
                 642 
                 third flange 
               
               
                   
                 643 
                 fitting shaft 
               
               
                   
                 644 
                 support recessed portion 
               
               
                   
                 645 
                 outer side face 
               
               
                   
                 646 
                 inner side face 
               
               
                   
                 647 
                 magnet ring 
               
               
                   
                 648 
                 tip end face 
               
               
                   
                 649 
                 mounting shaft 
               
               
                   
                 650 
                 fourth wheel 
               
               
                   
                 651 
                 fourth wheel main body 
               
               
                   
                 652 
                 fourth flange 
               
               
                   
                 653 
                 fitting shaft 
               
               
                   
                 654 
                 support recessed portion 
               
               
                   
                 655 
                 outer side face 
               
               
                   
                 656 
                 inner side face 
               
               
                   
                 658 
                 tip end face 
               
               
                   
                 661 
                 auxiliary member 
               
               
                   
                 662 
                 trunk portion 
               
               
                   
                 663 
                 locking flange 
               
               
                   
                 671 
                 follower wheel device 
               
               
                   
                 672 
                 second axle 
               
               
                   
                 701 
                 drive wheel device 
               
               
                   
                 702 
                 first axle 
               
               
                   
                 708 
                 gear 
               
               
                   
                 710 
                 first wheel 
               
               
                   
                 711 
                 first wheel main body 
               
               
                   
                 712 
                 first flange 
               
               
                   
                 713 
                 fitting shaft 
               
               
                   
                 714 
                 support recessed portion 
               
               
                   
                 715 
                 outer side face 
               
               
                   
                 716 
                 inner side face 
               
               
                   
                 717 
                 magnet ring 
               
               
                   
                 718 
                 tip end face 
               
               
                   
                 719 
                 mounting shaft 
               
               
                   
                 720 
                 second wheel 
               
               
                   
                 731 
                 follower wheel device 
               
               
                   
                 732 
                 second axle 
               
               
                   
                 751 
                 follower wheel device 
               
               
                   
                 752 
                 second axle 
               
               
                   
                 760 
                 fourth wheel 
               
               
                   
                 761 
                 fourth wheel main body 
               
               
                   
                 762 
                 fourth flange 
               
               
                   
                 763 
                 fitting shaft 
               
               
                   
                 764 
                 support recessed portion 
               
               
                   
                 765 
                 outer side face 
               
               
                   
                 766 
                 inner side face 
               
               
                   
                 768 
                 tip end face 
               
               
                   
                 770A 
                 carriage 
               
               
                   
                 770B 
                 carriage 
               
               
                   
                 770C 
                 carriage 
               
               
                   
                 770D 
                 carriage 
               
               
                   
                 771 
                 carriage frame 
               
               
                   
                 772 
                 main frame 
               
               
                   
                 773 
                 middle member 
               
               
                   
                 774 
                 recessed step portion 
               
               
                   
                 775 
                 locking lug 
               
               
                   
                 776 
                 longitudinal member 
               
               
                   
                 777 
                 lateral member 
               
               
                   
                 778 
                 outer face 
               
               
                   
                 778A 
                 coupling hole 
               
               
                   
                 781 
                 housing portion 
               
               
                   
                 782 
                 housing portion 
               
               
                   
                 789 
                 locking protrusion 
               
               
                   
                 800 
                 bearing plate 
               
               
                   
                 801 
                 fitting recessed portion 
               
               
                   
                 802 
                 support protruding portion 
               
               
                   
                 805 
                 protruding chip 
               
               
                   
                 806 
                 spring receiving portion 
               
               
                   
                 807 
                 spring insertion portion 
               
               
                   
                 821 
                 carriage frame 
               
               
                   
                 822 
                 main frame 
               
               
                   
                 823 
                 middle member 
               
               
                   
                 825 
                 locking lug 
               
               
                   
                 826 
                 longitudinal member 
               
               
                   
                 827 
                 lateral member 
               
               
                   
                 827B 
                 upper face 
               
               
                   
                 828 
                 outer face 
               
               
                   
                 828A 
                 coupling hole 
               
               
                   
                 831 
                 housing portion 
               
               
                   
                 832 
                 housing portion 
               
               
                   
                 835 
                 fixing member 
               
               
                   
                 836 
                 fitting hole 
               
               
                   
                 837 
                 center shaft 
               
               
                   
                 841 
                 fitting protrusion 
               
               
                   
                 842 
                 guide member 
               
               
                   
                 843 
                 guide groove 
               
               
                   
                 845 
                 guide groove 
               
               
                   
                 847 
                 conductive contact plate 
               
               
                   
                 848 
                 conductive contact plate 
               
               
                   
                 851 
                 powered toy vehicle 
               
               
                   
                 852 
                 toy vehicle main body 
               
               
                   
                 853 
                 chassis 
               
               
                   
                 854 
                 opening 
               
               
                   
                 855 
                 vehicle body 
               
               
                   
                 856 
                 gear box 
               
               
                   
                 857 
                 guide recessed portion 
               
               
                   
                 860 
                 locking groove 
               
               
                   
                 861 
                 toy passenger vehicle 
               
               
                   
                 862 
                 toy vehicle main body 
               
               
                   
                 863 
                 chassis 
               
               
                   
                 865 
                 vehicle body 
               
               
                   
                 868 
                 locking groove 
               
               
                   
                 870 
                 guide member 
               
               
                   
                 871 
                 guide groove 
               
               
                   
                 872 
                 conductive contact plate 
               
               
                   
                 873 
                 conductive contact plate 
               
               
                   
                 875 
                 electric component