Variable-wheel-gauge bogie for rolling stock

Abstract: Axle sleeves (7) are axially slidably mounted on an axle (4) restrained from rotation, and a wheel (8) is supported on a bearing (8) on each axle sleeve (7). A drive motor (10) mounted on each axle sleeve (7) drives the wheel (9) for rotation. A first and a second locking projection are formed on one end portion of each axle sleeve (7), and a locking recess is formed in the inside surface of a journal box (3). The axle sleeve (7) is locked at a position for a narrow rail gauge when the first locking projection is in engagement with the locking recess of the journal box (3) or at a position for a broad rail gauge when the second locking projection is in engagement with the locking recess of the journal box (3). The first or the second locking projection is kept in engagement with the locking recess by the weight of the journal box. A conical locking projection (15A, 15B) and a locking hole (16) are kept in engagement by the weight of a truck frame. A vibration isolating unit (18) for locking projection is fitted in the locking hole (16) to hold elastically the conical locking projection (15A, 15B) as fitted in the locking hole (16).

Description: The present invention relates to a variable-wheel-gauge bogie for rolling stock and a wheel gauge changing track arrangement and, more particularly, to a variable-wheel-gauge bogie capable of automatically adjusting its wheel gauge to a rail gauge of a track, and the wheel gauge changing track arrangement for changing the wheel gauge of the variable-wheel-gauge bogie. Description of the Prior Art There have been proposed various variable-wheel-gauge bogies for rolling stock intended for use on a track of a standard rail gauge of 1435 mm, such as tracks for the Shinkansen line, and on a track of a narrow rail gauge of 1067 mm, such as a track for the old line, and various wheel gauge changing track arrangements. A wheel gauge changing technique disclosed in, for example, JP-A No. 5-39036 employs a car lifting device, such as a pneumatic cylinder actuator, mounted on a railroad car and changes the wheel gauge of a bogie supporting the railroad car by lifting up the railroad car by the car lifting device and shifting the wheels by actuators after stopping the railroad car. In a variable-wheel-gauge bogie disclosed in JP-A No. 6-40335, a tubular sliding shaft is mounted on an axle restrained from rotation, wheels are supported on bearings on a tubular sliding shaft and a stator of a drive motor is fixedly coupled with the tubular sliding shaft, and the sliding shaft is moved axially to move both the wheels and the drive motor for wheel gauge changing. Journal boxes, the axle and the sliding shaft are provided with through holes for receiving power-driven positioning-and-locking pins. The wheels are positioned and locked in place in a desired wheel gauge by fitting the positioning-and-locking pins in the corresponding through holes of the journal boxes, the axle and the sliding shaft, respectively, to unite the journal boxes, the axle and the sliding shaft fixedly. Since locked in place, the wheels are unable to move transversely so that a fixed wheel gauge is maintained while the variable wheel gate bogie is traveling. In a variable-wheel-gauge bogie for rolling stock, disclosed in JP-A No. 5-246329, journal boxes supporting the axles of independent wheels are supported on a wheel frame by a parallel linkage. A car support base is installed along a gauge changing section of a track. When a railroad car supported on the variable-wheel-gauge bogie enters the gauge changing section at a low traveling speed, the weight of the railroad car is born by the car support base to relieve the wheels of the weight of the railroad car, so that the links of the parallel linkage supporting the unloaded wheels are able to move freely and the wheel gauge can be adjusted to a rail gauge. The wheels are fixed in place by fitting pins in holes formed at the opposite ends of the parallel linkage. Reference is made in "Rapid Trains and Sleeping Cars in Europe", Sharyou Gijutsu, No. 163, Nippon Tetsudo Sharyo Kogyo-kai FDN to a Talgo automatic wheel gauge changing system for railroad cars of the French National Railways and the Spanish National Railways that travel on both standard tracks of the standard gauge of 1435 mm and broad tracks of the broad gauge of 1668 mm. The railroad car of the Talgo automatic wheel gauge changing system is not equipped with any driving mechanism for locomotion, and employs independent wheels that are not connected by a single axle or the like and move transversely together with their axles for changing the wheel gauge. When the railroad car passes a gauge changing section, the weight of the railroad car is born by additional load bearing rails laid along the rails of the gauge changing section to relieve the wheels of the weight of the railroad car, so that the wheels are able to move freely transversely for automatic wheel gauge changing while the railroad car is traveling. The wheel gauge changing systems disclosed in JP-A Nos. 5-39036 and 6-40335, however, need to lift up all the railroad cars of a train simultaneously for wheel gauge changing operation by the car lifting devices while the railroad cars are stopped. Therefore the wheel gauge chang-ing operation takes much time and, when the train consists of a large number of railroad cars, many car lifting devices or a very long car support structure is necessary. In a wheel positioning-and-locking mechanism using the positioning-and-locking pins, the diameter of the through holes must be slightly larger than that of the corresponding positioning-and-locking pins to enable the positioning-and-locking pins to be smoothly fitted in the through holes when positioning and locking the wheels in place. Therefore, the wheel positioning-and-locking mechanism for locking the wheel in place unavoidably permits play and, consequently, each pair of wheels on an axle move individually transversely and the wheel gauge varies minutely and continually. Such a minute variation of the wheel gauge enhances the meandering motion of the railroad car during high-speed traveling, causing problems including spoiling riding comfort in the traveling performance of the railroad car. A very high impulsive transverse force acts on the bogie when the bogie travels along a curve or passes a railroad switch. Therefore, the play between the components of the wheel positioning-and-locking mechanism cause problems including distortion, breakage and abrasion of the structural components of the bogie that shortens the life of the bogie. Since the journal box is not fixed and is elastically suspended from the frame of the bogie by an axle spring, a special means is necessary for aligning the through hole of the journal box with those of the axle and the sliding shaft. Since the wheel gauge changing system disclosed in JP-A No. 5-246329 shifts the wheels by the turning motion of the links of the parallel linkage when changing the wheel gauge of the railroad car, the force generated by the weights of the wheels, the axle and the journal boxes and acting on an elongate axle guide member increases as the parallel links approach a horizontal position. Consequently, the elongate axle guide member is liable to be distorted or broken and hence the wheel gauge changing system is unsatisfactory in reliability. Although the Talgo automatic wheel gauge changing system that shifts each pair of independent wheels transversely together with the journal boxes is suitable for application to a single axle bogie, the Talgo automatic wheel gate changing system has structural difficulties in applying the same to a two-axle bogie. It is very difficult to apply the Talgo automatic wheel gauge changing system to a bogie for narrow rail gauge because of dimensional restrictions thereon. FR-A-2383810 discloses a variable wheel gauge system for rolling stock, the rolling stock having a variable wheel gauge bogie comprising journal boxes suspended from side beams of a truck frame by elastic members, axles vertically movably supported on the journal boxes and axle sleeves axially slidably mounted on the axles for movement between a broad gauge and a narrow gauge position. Wheels are supported for rotation on bearings on the axle sleeves and on-sleeve locking members are formed on an outer circumference of the axle sleeves. On-box locking means are formed on the journal boxes, capable of engaging with the on-sleeve locking members to restrain the axle sleeves from axial movement when each of the axle sleeves is at its broad gauge or narrow gauge position and when the weight of the truck frame act thereon through the journal boxes. The document further discloses wheel gauge changing rails interconnected to rails of a broad gauge and those of a narrow gauge, and car support rails extended on an outer side of, and along said wheel gauge changing rails, the rails of the broad gauge and the rails of the narrow gauge, so as to come into engagement with the journal boxes to raise the journal boxes relative to the axle sleeves so that the locking means is disengaged. The document further discloses pairs of journal boxes suspended from side beams of a truck frame by elastic members, and provided with locking means in their upper walls respectively; car support units each formed on the lower surface of each journal box to support the body of a railroad car when changing the wheel gauge; axles vertically movably supported on the journal boxes with the opposite ends thereof contained in the journal boxes, respectively; pairs of axle sleeves axially slidably fitted on the axles, respectively, for movement between a broad gauge position and a narrow gauge position; pairs of wheels supported for rotation on the pairs of axle sleeves; pairs of locking blocks attached to the outer circumference of the pairs of axle sleeves, each having an upper surface for bearing the weight of the railroad car through the journal box and locking projections projected from the upper surface of each locking block to be engaged with the locking means of the journal boxes when the axle sleeve is at a position for the broad gauge of a narrow gauge. It is accordingly an object of the present invention to provide a system for changing the gauge of a rolling stock bogie which at least partially overcomes the difficulties of the prior art. It is a further object of the present invention to provide a variable-wheel-gauge bogie of rolling stock which at least partially mitigates the difficulties of the prior art. An embodiment of the present invention provides a variable-wheel-gauge bogie for rolling stock, capable of changing its wheel gauge while traveling and of functioning with high safety and reliability, and applicable to railroad cars for narrow gauges and those equipped with drive motors, and to provide a wheel gauge changing track arrangement for use in combination with the variable-wheel-gauge bogie. Another embodiment of the invention provides a variable-wheel-gauge bogie for rolling stock, having a wheel positioning-and-locking mechanism capable of locking wheels in place without permitting any play with high safety and reliability. According to one aspect of the present invention there is provided a system for changing the gauge of a rolling stock bogie having, a pair of side beams for supporting wheel axles on a railroad via wheels, journal boxes provided under said side beams, respectively, to receive ends of said wheel axles, and axle sleeves rotably supporting said wheels, thereon and fitted on said wheel axles slidably along the wheel axles, respectively, comprising: first engagement means formed on an outer peripheral surface of each of said axle sleeves; second engagement means formed on an inside surface of each of said journal boxes and provided to selectively engage said first engagement means when said wheels are positioned to match one of different gauges; wheel gauge changing rails laid between two rails of different gauges and provided to allow said rolling stock bogie to roll thereon; and car support rails provided in parallel with said wheel gauge changing rails to separate the rolling stock bogie from said sleeves and said wheels in a vertical direction to disengage said second engagement means from said first engagement means while said rolling stock bogie rolls on said wheel gauge changing rails so as to change said gauge without stopping the rolling stock bogie; characterized by: a fastening device for fastening together each of said journal boxes and each of said wheel axles to restrain the journal boxes from vertical movement relative to the wheel axles and to release the journal boxes from the wheel axles before the rolling stock bogie starts travelling on the wheel gauge changing rails. Preferably, each axle is provided with circular grooves in its end portions, respectively, each journal box has an extension fitted in the circular groove of the axle, the fastening device has a wedge member held adjacent to the extension so as to be forced into the circular groove of the axle, and wedge biasing members for biasing the wedge member toward the circular groove, the wedge member presses the extension against the side surface of the annular groove by its wedging action when forced into the circular groove of the axle to fasten together the journal box and the axle. Desirably, each car support rail has a wedge guide rail transversely projecting therefrom and capable of retracting the wedging member from the circular groove of the axle against the biasing force of the wedge biasing members to disengage the journal box from the axle. Preferably, the wheel gauge changing track arrangement further comprises guide rails laid so as to extend on both sides of and along the wheel gauge changing rails and to come into contact with the side surfaces of the wheels, and biasing members for biasing the guide rails to bring the guide rails into contact with the side surfaces of the wheels. Desirably, each journal box is provided with shims for thickness adjustment on its lower surface that comes into contact with the car support rail. According to a second aspect of the present invention there is provided a variable-wheel gauge bogie of rolling stock, for automatically changing its wheel gauge while travelling on wheel gauge changing rails interconnecting rails of a broad-gauge track of a broad rail gauge and rails of a narrow gauge track of a narrow rail gauge, said variable-wheel-gauge bogie comprising: journal boxes suspended from side beams of a truck frame by elastic members, respectively; axles vertically movably supported on the journal boxes; an axle sleeve axially slidably fitted on each of the axles for movement between a position for the broad rail gauge and a position for the narrow rail gauge; wheels supported for rotation on the axle sleeves, respectively; drive motors for driving the wheels in rotation supported on the axle sleeves, respectively; on-sleeve locking members formed on the outer circumferences of the axle sleeves, respectively; and an on-box locking means formed on the journal boxes, for engaging with the on-sleeve locking members, respectively, to restrain the axle sleeves from the axial movement when each of the axle sleeves is at a position for the broad rail gauge or at a position for the narrow rail gauge, and when the weight of the truck frame acts thereon through the journal boxes: characterized by: fastening devices each for fastening together the journal box and the corresponding axle to restrain the journal box from vertical movement relative to the axle sleeve, and for disengaging the journal box from the axle immediately before the variable-wheel-gauge bogie starts travelling on the wheel gauge changing rails; and car support units each formed on the lower surface of each journal box to support the body of the bogie when changing the wheel gauge. According to a third aspect of the present invention there is provided a variable-wheel-gauge bogie of rolling stock, for automatically changing wheel gauge while a railroad car is travelling on wheel gauge changing rails interconnecting rails of a broad-gauge track of a broad gauge and rails of a narrow-gauge track of a narrow gauge, said variable-wheel-gauge bogie comprising: pairs of journal boxes suspended from side beams of a truck frame by elastic members, and provided with locking means in their upper walls, respectively; car support units each formed on the lower surface of each journal box to support the body of a railroad car when changing the wheel gauge; axles vertically movably supported on the journal boxes with the opposite ends thereof contained in the journal boxes, respectively; pairs of axle sleeves axially slidably fitted on the axles, respectively, for movement between a position for the broad rail gauge and a position for the narrow rail gauge; pairs of wheels supported for rotation on the pairs of axle sleeves, respectively; pairs of locking blocks attached to the outer circumferences of the pairs of axle sleeves, respectively, and each having an upper surface for bearing the weight of the railroad car through the journal box; and locking projections projecting from the upper surface of each locking block so as to be engaged with the locking means of the journal boxes when the axle sleeve is at a position for the broad rail gauge or the narrow rail gauge; characterized in that: said locking means are locking holes formed in the upper walls of the journal boxes so as to allow fitting engagement of the locking projections therein; each of the locking projections is a conical projection having a lower cylindrical portion of a substantially fixed diameter and a predetermined height, and an upper taper conical portion; each of the locking holes has a lower section of a diameter substantially equal to that of the cylindrical portion of the conical locking projection, and an upper section of a diameter greater than that of the lower section; and vibration isolating units are each provided in each of the locking holes so as to surround the taper conical portion to be in elastic contact with the conical portion. Desirably, the variable-wheel-gauge bogie is provided with central stoppers each projecting from the middle portion of each axle to restrain the axle sleeve from moving beyond the position for the narrow rail gauge toward the middle of the axle, end stoppers projecting from the oppo- site end portions of each axle to restrain the axle sleeves from moving beyond the positions for the broad rail gauge toward the ends of the axle, sliding members projecting from both sides of each end stopper and each having a taper upper end, guide cavities formed in each journal boxes to guide the sliding members for vertical movement, respectively, and vibration isolating units each disposed in an upper portion of each guide cavity so as to be in elastic contact with the surface of the taper upper end of the sliding member. Desirably, the vibration isolating unit for locking pro-jection comprises an outer ring fixedly fitted in the upper section of the locking hole, a rubber vibration isolator fixed to the inside surface of the outer ring, and an inner ring fixed to the inside surface of the rubber vibration isolator, and the inner ring is moved by the conical portion of the conical locking projection to deform the rubber vibration isolator when the conical locking projection is fitted in the locking hole. Preferably, the vibration isolating unit for locking projection has a annular plate spring having a V-shaped section. Desirably, the vibration isolating unit for locking projection comprises a wedge ring fitted in the upper section of the locking hole, a cover covering the upper open end of the upper section of the locking hole, and an elastic member disposed between the upper surface of the wedge ring and the cover to bias the wedge ring downward, the conical portion of the conical locking projection comes into engagement with the inner circumference of the wedge ring when the conical locking projection is fitted in the locking hole. Preferably, the sliding members are outward extensions of the opposite side surfaces of the end stopper, and the guide cavities are sliding grooves formed in the opposite side walls of the journal box. Desirably, the vibration isolating unit for sliding member comprises a box fitted in an opening formed in each side wall of the journal box, detachably attached to the sides wall and having a recess opening into the interior of the journal box, a rubber vibration isolator attached to the surface of the recess of the box, and a liner fixed to the rubber vibration isolator so as to be in contact with the taper upper end of the sliding member. Preferably, the vibration isolating unit for sliding member has a plate spring having a V-shaped cross section and in elastic contact with the end surface of the taper upper end portion and the opposite side surfaces of the sliding member. Desirably, the sliding members are pins projecting upward from brackets projecting from the opposite side surfaces of the end stopper, and the guide cavities are vertical through holes formed in the journal box. Preferably, the vibration isolating unit for sliding member comprises an outer ring fixedly disposed in the upper portion of the guide cavity, a rubber vibration isolator fixed to the inside surface of the outer ring, and an inner ring fixed to the inside surface of the rubber vibration isolator, and the inner ring is moved by the taper upper end of the sliding member so as to deform the rubber vibration isolator when the sliding member is inserted in the guide cavity. In an embodiment,the wheel gauge can be changed without stopping the railroad car while the railroad car is traveling, and the present invention is applicable to railroad cars for narrow gauges and railroad cars mounted with drive motors. Since the locking members on the journal boxes, for restraining the axle sleeves from axial movement engage with the locking members on the axle sleeves, respectively, when the weight of the railroad car acts thereon, the locking members are engaged securely so that the variable-wheel-gauge bogie for rolling stock functions with high safety and high reliability. Since the conical locking projections are surely fitted in the locking holes and the vibration isolating units come into elastic contact with the circumferences of the conical locking projections, respectively, dynamic shocks attributable to the play of the conical locking projections in the corresponding locking holes is absorbed, which prevents the abrasion of parts and ensures highly stabilized traveling performance. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a schematic plan view of a variable-wheel-gauge bogie in a first embodiment according to the present invention; Fig. 1B is a side view of the variable-wheel-gauge bogie of Fig. 1A; Fig. 2 is a fragmentary longitudinal sectional view of a variable-wheel-gauge bogie in the first embodiment as set in a geometry for a narrow rail gauge; Fig. 3 is a fragmentary longitudinal sectional view of the variable-wheel-gauge bogie in the first embodiment as set in a geometry for a standard rail gauge; Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 3; Fig. 5 is a longitudinal sectional view taken along the line V-V in Fig. 4; Fig. 6 is a side view showing the relation between an axle, a journal box and a locking member included in the variable-wheel-gauge bogie of Fig. 2; Fig. 7A is a plan view of a wheel gauge changing track arrangement in the first embodiment; Fig. 7B is a side view of the wheel gauge changing track arrangement of Fig. 7A; Fig. 8 is an enlarged longitudinal sectional view of an axle and the associated components included in a variable-wheel-gauge bogie in a second embodiment according to the present invention; Fig. 9 is an enlarged side view of a journal box and the associated components included in the variable-wheel-gauge bogie in the second embodiment; Fig. 10 is a plan view showing the relation between a journal box and a locking block included in the variable-wheel-gauge bogie in the second embodiment; Fig. 11 is a cross-sectional view taken along the line XI-XI in Fig. 8; Fig. 12 is a longitudinal sectional view showing the relation between a locking hole and a conical locking projection included in a variable-wheel-gauge bogie in the second embodiment; Fig. 13 is a half-sectional view corresponding to Fig. 12; Fig. 14 is a sectional view showing the relation between a sliding member and a vibration isolating unit included in a variable-wheel-gauge bogie in the second embodiment; Fig. 15 is a sectional view taken along the line XV-XV in Fig. 14; Fig. 16 is a sectional view taken along the line XVI-XVI in Fig. 15; Fig. 17 is a fragmentary cross-sectional view of a wheel gauge changing track arrangement; Fig. 18 is a half-sectional view of a modification of the vibration isolating unit; Fig. 19 is a longitudinal sectional view of a vibration isolating unit in another modification; Fig. 20 is a plan view of a wedging ring; Fig. 21 is a sectional plan view of a vibration isolating unit for a sliding member; Fig. 22 is a sectional side view of a vibration isolating unit for a sliding member; Fig. 23 is a side view of a vibration isolating unit for a sliding member; and Fig. 24 is a plan view of a vibration isolating unit for a sliding member. A first embodiment of the present invention will be described hereinafter with reference to Figs. 1 to 7. First the construction of a variable-wheel-gauge bogie for rolling stock will be described. Referring to Fig. lA, journal boxes 4 are suspended from the side beams 1 of a truck frame by axle springs 2, i.e., elastic members. The axle springs 2 may be coil springs, pneumatic springs or rubber springs. The flat lower surfaces of the journal boxes 3 serving as sliding surfaces 3a are at the same level. Fixed axles 4 are supported on the journal boxes 3. Referring to Figs. 1B, 2 and 3, a positioning projection 5 is formed on each axle 4 at the middle of the axle 4, and positioning circular grooves 6 are formed in each axle 4 at some distance from its opposite ends. Two axle sleeves 7 are put on each axle 4 so as to be axially movable on the axle 4. Each axle sleeve 7 is supported on the journal box 3 and restrained from rotation by a locking block 13. The axle 4 and the axle sleeve 7 are not restrained from rotation relative to each other. A wheel 9 is supported for rotation on a taper roller bearing 8 at a substantially middle portion of the axle sleeve 7. Preferably, the wheel 9 is an elastic wheel formed of a composite material that will reduce the unsprung weight of the bogie and vibrational acceleration. A stator 10a included in a drive motor 10 is fixedly mounted on the axle sleeve 7 at a position on one side of the wheel 9 nearer to the middle of the axle 4. A rotor 10b included in the drive motor 10 has one end supported on a bearing 11 on the axle sleeve 7 and the other end fixed to a side surface of the wheel 9. A brake disk 12 is formed on the outer circumference of the rotor 10b. The tubular locking block 13 is mounted on a portion of the axle sleeve 7 near the end of the axle 4 and fixedly joined to the axle sleeve 7 by splines 14. The locking block 13 extends into the journal box 3, has sliding side walls 13a as shown in Fig. 4 and is able to move vertically relative to the journal box 3. As shown in Fig. 4, the locking block 13 has a pair of upper inclined surfaces 13b, and two axially elongate locking projections 15A and 15B of the same shape are formed on each upper inclined surface 13b as shown in Fig. 5. The locking projections 15A and 15B has a trapezoidal longitudinal section. The center distance between the locking projections 15A and 15B is equal to half the difference between a broad rail gauge and a narrow rail gauge. More concretely, the broad rail gauge is the standard rail gauge of 1435 mm and the narrow rail gauge is 1067 mm in this embodiment, and hence the center distance between the locking projections 15A and 15B is (1435 - 1067)/2 = 184 mm. Locking groove 16 having a shape complementary to that of the locking projections 15A and 15B are formed in the inside surface of the journal box 3 facing the upper inclined surfaces 13b of the locking block 13. When the locking projection 15A or 15B is fitted in the corresponding locking recess 16 as shown in Fig. 5, the axle sleeve 7 is unable to move axially. The positional relation between the locking projections 15A and 15b and the corresponding locking recess 16 is determined so as to meet the following conditions. The distance between the pair of wheels 9 on each axle 4 corresponds to the narrow rail gauge as shown in Fig. 2 when the locking projection 15A is fitted in the locking recess 16, and the distance between the pair of wheels 9 corresponds to the broad rail gauge as shown in Fig. 3 when the locking projection 15B is fitted in the locking recess 16 as shown in Fig. 5. The locking projections 15 and the locking recess 16 are locking part of the axle sleeve 7 and that of the journal box 3, respectively, may be formed in any suitable shape other than the trapezoidal shape, provided that the locking projections 15 and the locking recess 16 are able to restrain the axle sleeve 7 from axial movement when engaged. Although this embodiment is provided with the two locking projections 15 and the one locking recess 16, the locking block may be provided with one locking projection 15 and the journal box 3 may be provided with two locking recesses 16. The journal box 3 may be provided with a locking projection or two locking projections and the locking block 13 may be provided with two locking recesses or one locking recess. As shown in Figs. 2 and 3, the journal box 3 has a sliding guide extension 17 having vertical guide legs. The guide legs extend vertically on the opposite sides of a reduced part of the axle 4 defined by the circular groove 6 formed in the end portion of the axle 4. The guide legs of the guide extension 17 receiving the reduced portion of the axle 4 therebetween guides the journal box 3 when the journal box 3 move vertically relative to the axle 4 and the axle sleeve 7. The guide extension 17 serves also as a stopper for limiting the outward axial movement of the axle sleeve 7. Referring to Figs. 2, 3 and 6, a bifurcate fastening member 18 is inserted in the circular groove 6 of the axle 4. The fastening member 18 has two wedging legs 18a and 18b. A pair of rods 19 are joined to the fastening member 18, and coil springs 20 are extended between the lower ends of the rods 19 and the journal box 3, respectively, to bias the rods 19 downward. Thus, the fastening member 18 is biased downward through the rods 19 by the coil springs 20 so that the wedging legs 18a are inserted in the circular groove 6. The working surfaces of the guide extension 17 or the fastening member 18 are longitudinally tapered. When the wedging legs 18a are forced into the circular groove 6 by the resilience of the coil springs 20, the guide extension 17 is pressed firmly against the side surface of the circular groove 6 of the axle 4 by a wedging action. Consequently, the journal box 3 and the axle 4 are firmly united together to prevent perfectly the vertical movement of the journal box and the axle 4 relative to each other. A wheel gauge changing track arrangement will be described hereinafter. Referring to Figs. 7A and 7B showing part of a narrow track of a narrow gauge having narrow-track rails 21, part of a standard track of the standard rail gauge having standard-track rails 22, the narrow-track rails 21 and the standard-track rails 22 are interconnected by a wheel gauge changing track having wheel gauge changing rails 23. The rail gauge of the wheel gauge changing track having the wheel gauge changing rails 23 increases gradually from one end thereof joined to the narrow track having the narrow-track rails 21 toward the other end thereof joined to the standard track having the standard-track rails 22. Portions of the narrow-track rails 21 and the standard-track rails 22 in sloping sections L of a predetermined length continuous with the wheel gauge changing track are declined toward the joints of the narrow-track rails 21 and the wheel gauge changing rails 23, and those of the standard-track rails 22 and the wheel gauge changing rails 23, respectively, so that the joints are sunk by a predetermined height H from the level of the narrow track and the standard track. Guide rails 24 are laid on both sides of each wheel gauge changing rails 23 along the entire length of the wheel gauge changing rails 23 and portions of the narrow-track rails 21 and the standard-track rails 22 continuous with the wheel gauge changing rails 23. The opposite guide rails 24 are biased toward each other by springs 25 so that the guide rails 24 are pressed against the side surfaces of the wheels 4, respectively. A pair of car support rails 26 are laid on the outer side of two sets each of the rails 21, 22 and 23, respectively, so as to extend in a substantially horizontal plane at a predetermined height from the ground. The car support rails 26 are laid so as to extend right under the sliding surfaces 3a of the journal boxes 3 so that the sliding surfaces 3a of the journal boxes 3 come into sliding contact with the car support rails 26. As shown in Figs. 2 and 3, fastening member raising rails 27 are supported on the car support rails 26 so as to extend on the outer side of the car support rails 26 and right under the rods 19 joined to the fastening members 18. Each fastening member raising rail 27 has a sloping section 1 corresponding to a section of the narrow-track rail 21 continuous with the sloping section L, and sloping up toward a horizontal section corresponding to the the sloping section L continuous with the narrow-track rail 21, the horizontal section of the wheel gauge changing rail 23 and the sloping section L continuous with the standard-track rail 22, and a sloping section 1 corresponding to a section of the standard-track rail 22 continuous with the other sloping section L, and sloping down from the horizontal section. The operation of the first embodiment will be described hereinafter on an assumption that the railroad car travels from the narrow-track rails 21 of the narrow track to the standard-track rails 22 of the standard track. Referring to Figs. 7A and 7B, the variable-wheel-gauge bogie is in the geometry shown in Fig. 2 while the railroad car is traveling on the narrow-track rails 21 and the locking projections 15A are fitted in the locking recesses 16, respectively. The rotors 10b of the drive motors 10 rotate together with the wheels 9, respectively. Reactive torques corresponding to the driving torques of the wheels 9 are transmitted through the axle sleeves 7, the sliding side walls 13a of the locking blocks 13, the journal boxes 3 and the axle springs 2 to the side beams 1 of the truck frame to drive the railroad car for traveling. When the variable-wheel-gauge bogie enters a section of the narrow-track rails 21 corresponding to the up sloping section 1 of the raising rails 27, the raising rails 27 raises the rods 19 against the force of the springs 20 to raise the fastening members 18 by a predetermined distance. Consequently, the wedging effects of the fastening members 18 are removed, whereby the journal boxes 3 are able to move vertically relative to the axles 4. Subsequently, the variable-wheel-gauge bogie enters the down sloping section L of the narrow-track rails 21 and starts traveling downward. Immediately after the variable-wheel-gauge bogie has started traveling downward, the sliding surfaces 3a of the journal boxes 3 come into contact with the car support rails 26, and then the journal boxes 3 are kept in a substantially horizontal plane while the axles 4 and the axle sleeves 7 move downward relative to the journal boxes 3 according to the inclination of the down sloping section L. Consequently, the locking projections 15A come off the corresponding locking recesses 16 to allow the axle sleeves 7 to move axially. The axle sleeves 7 are allowed to move axially before the variable-wheel-gauge bogie reaches the terminal end of the down sloping section L at the latest. Then, the variable-wheel-gauge bogie starts traveling on the wheel gauge changing rails 23 of the wheel gauge changing track gradually widening toward the standard track. Then, the wheels 9 are guided by the guide rails 24 biased toward the wheels 9 by the springs 25 as the wheels roll on the wheel gauge changing rails 23, so that the wheels 9 are shifted gradually outward together with the associated axle sleeves 7 on the axles 4. When the variable-wheel-gauge bogie arrives at the terminal end of the wheel gauge changing rails 23, the outer ends of the sleeves 7 come into contact with the extensions 17 of the corresponding journal boxes 3 as shown in Fig. 3, and the axle sleeves 7 are stopped. In this state, the distance between the pair of wheels 9 on each axle 4 is equal to the standard rail gauge, and the locking projections 15B are located opposite to the locking recesses 16, respectively. Since the truck frame of the variable-wheel-gauge bogie is supported through the journal boxes 3 on the car support rails 26 while the variable-wheel-gauge bogie is traveling on the wheel gauge changing rails 23 or on sections of the narrow-track rails 21 or the standard-track rails 22 near the ends of the wheel gauge changing rails 23, the wheels 9 and the axle sleeves 7 are lightly loaded, and hence the axle sleeves 7 are able to slide lightly according to the variation of the rail gauge of the wheel gauge changing track. Then, the variable-wheel-gauge bogie moves from the wheel gauge changing rails 23 to the standard-track rails 22. While the variable-wheel-gauge bogie is traveling in the up sloping section L of the standard-track rails 22, the axles 4 and the axle sleeves 7 move upward relative to the journal boxes 3, the locking projections 15B approach the corresponding locking recesses 16 of the journal boxes and, finally, the locking projections 15B are fitted in the corresponding locking recesses 16. Consequently, the axle sleeves 7 is locked in place and the wheels 9 are fixed at positions for the standard rail gauge. Then, as the variable-wheel-gauge bogie travels in a section of the standard track corresponding to the down sloping section 1 of the guide rails 27, the fastening members 18 are lowered through the rods 19 by the springs 20, and press the guide extensions 17 against the axles 4 by their wedging effect to fasten the axle sleeves 7 firmly to the axles 4. The variable-wheel-gauge bogie is provided with the fastening members 18 for the following purposes. The locking projection 15B of each axle sleeve 7 is fitted in the locking recess 16 of the journal box 3 as the journal box 3 is lowered by the weight of the truck frame when the variable-wheel-gauge bogie travels on the standard-track rails 22 in the up sloping section L. Therefore, even if the variable-wheel-gauge bogie bounces, the locking projection 15B will not come off the locking recess 16 because a vertical acceleration is in the range of about 0.3g to 0.5g and far less than the gravitational acceleration of lg. However, since the axle springs 2 can be transversely slightly displaced due to their rigidity, there is the possibility that the wheels 9 move relative to the axle 4 and the components of the variable-wheel-gauge bogie chatters and are abraded if the play of the extensions 17 of the journal boxes 3 in the corresponding circular grooves 6 of the axles 4 is permitted. Therefore, the play of the extensions 17 in the corresponding circular grooves 6 is inhibited perfectly by the wedging action of the fastening members 18 to solve the aforesaid problems. When a train of a plurality of railroad cars pass the wheel gauge changing track arrangement of Figs. 7A and 7B, it is desirable to stop the drive motors 10 of the railroad car traveling in a section of the track corresponding to the wheel gauge changing track arrangement. The railroad car may be provided with a sensor for detecting the wheel gauge changing arrangement and supply of power to the drive motors 10 may be stopped upon the detection of the wheel gauge changing arrangement by the sensor. The operation of the first embodiment when the railroad car travels from the standard-track rails 22 of the standard track to the narrow-track rails 21 of the narrow track is reverse to the foregoing operation of the same and hence the description of the former will be omitted. In this embodiment, a stack of a plurality of height adjusting shims 50 are fastened to the sliding surface 3a of the journal box 3 with screws as shown in Figs. 2, 3, 4 and 6. The diameter of each wheel 9 decreases as the wheel 9 is abraded and the distance between the sliding surface 3a of each journal box 3 and the car support rail 26 decreases. Therefore, some of the shims 50 are removed according to the reduction of the diameter of the wheel 9 to compensate a reduction in the distance between the sliding surface 3a of the journal box 3 and the car support rail 26. Although the entire length of the car support rails 26 is extended in a horizontal plane and the sloping sections L are formed in sections of the narrow-gauge track and the standard-gauge track continuous with the wheel gauge changing rails 23 of the wheel gauge changing track in this embodiment, the respective rails 21, 22 and 23 of the narrow-gauge track, the standard-gauge track and the wheel gauge changing track may be extended in a horizontal plane and sloping sections may be formed in the car support rails 26. Maintenance work including changing the wheels 9 and the taper roller bearings 8 will be greatly simplified when the locking block 13 is detachable from the axle sleeve 7, and the section of the axle sleeve 7 in which the locking block 13 is mounted on the axle sleeve 7 is formed in an outside diameter smaller than the inside diameter of the taper roller bearing 8. Since the wheels 9 are guided by the guide rails 24 biased by the springs 25 so as to be in contact with the side surfaces of the wheels 9, the wheels 9 can be very smoothly shifted according to the variation of the rail gauge of the wheel gauge changing track for wheel gauge adjustment. A variable-wheel-gauge bogie in a second embodiment of the present invention will be described hereinafter with reference to Figs. 8 to 24. The variable-wheel-gauge bogie in the second embodiment is similar in construction to the variable-wheel-gauge bogie in the first embodiment and hence only components and arrangements of the variable-wheel-gauge bogie different from those of the variable-wheel-gauge bogie in the first embodiment will be described. Referring to Figs. 8, 9 and 11, a tubular locking block 13 is fixedly united to on end of an axle sleeve 7 on the side of the end of an axle 4. As best shown in Fig. 11, male splines are formed in a portion of the axle sleeve 7, and female splines mating with the male splines are formed on the locking block 13 to inhibit the rotation of the axle sleeve 7 and the locking block 13 relative to each other. Since the locking block 13 is supported on the journal box 3 so that the locking block 13 is unable to rotate, which will be described later, the axle sleeve 7 is unable to rotate. The locking block 13 is fastened to the axle sleeve 7 with a nut 28 as shown in Fig. 8 so that the locking block 13 is unable to move axially relative to the axle sleeve 7. The locking block 13 is contained in the journal box 3. As shown in Fig. 11, the locking block 13 has a horizontal, load bearing upper surface 13a in contact with the upper wall of the journal box 3 to take the weight of a truck frame through the journal box 3, and sliding side surfaces 13b in contact with a sliding side guide surfaces formed in the journal box 3. As shown in Figs. 8 and 10, a pair of conical locking projections 15A and 15B project from the upper surface 13a of the locking block 13. The conical locking projections 15A and 15B are spaced apart by a predetermined distance. The center distance between the conical locking projections 15A and 15B is equal to half the difference between a broad rail gauge and the standard rail gauge. More concretely, in this embodiment, the broad rail gauge, i.e., a standard rail gauge, is 1435 mm and the narrow rail gauge is 1067 mm. Therefore, the center distance between the conical locking projections 15A and 15B is (1435 - 1067)/2 = 184 mm. A locking hole 32 and an escape hole 33 are formed in the upper wall of the journal box 3. The distance along the axis of an axle 4 between the locking hole 32 and the escape hole 33, i.e., the center distance, is equal to the center distance between the conical locking projections 15A and 15B. When the conical locking projection 15A or 15B is fitted in the locking hole 32, the axle sleeve 7 is unable to move axially. The positional relation between the conical locking projections 15A and 15B and the locking hole 32 is determined so as to meet the following conditions. The wheel 9 is at a position indicated by continuous lines in Fig. 8 corresponding to the narrow rail gauge when the conical locking projection 15A is fitted in the locking hole 32, and the wheel 9 is at a position indicated by alternate long and two short dashes lines in Fig. 8 corresponding to the broad rail gauge when the conical locking projection 15B is fitted in the locking hole 32. The conical locking projection 15A is received in the escape hole 33 when the conical locking projection 15B is fitted in the locking hole 32. The diameter of the escape hole 33 is far greater than the conical locking projection 15A. Referring to Figs. 12 and 13, each of the conical locking projections 15 (the reference numeral 15 will be used to indicate both the conical locking projections 15A and 15B inclusively) has a cylindrical lower portion 15a and a conical head portion 15b. The cylindrical lower portion 15a has a height h and a uniform diameter through the height h. The conical head portion 15b is tapered upward. The locking hole 32 of the journal box 3 has a lower section 32a of a height h and an upper section 32b. The diameter of the lower section 32a is slightly greater than that of the cylindrical lower portion 15a, and the diameter of the upper section 32b is far greater than that of the lower section 32a. A vibration isolating unit 34 for the conical locking projection 15 is fitted in the upper section 32b of the locking hole 32. The vibration isolating unit 34 comprises an outer ring 35 detachably fixed to the circumference of the upper section 32b, an annular rubber vibration isolator 35 fixed to the inner circumference of the outer ring 35, and an inner ring 36 fixed to the inner circumference of the rubber vibration isolator 37. The outer ring 35 is provided with an inner flange 35a serving as a retainer for retaining the inner ring 36 or the rubber vibration isolator 37, and an outer flange 35b. The outer flange 35b is fastened detachably to the journal box 3 with screws 39. The vibration isolating unit 34 in a natural state, when none of the conical locking projections 15 is fitted in the locking hole 32, a predetermined clearance is formed between the inner ring 36 or the rubber vibration isolator 37, and the inner flange 35a as shown in Fig. 13. Referring to Figs. 14, 15 and 16, an end stopper 40 projects from each end of an axle 4, and sliding members 41 extend perpendicularly to the axis of the axle 4 from the opposite sides of the end stopper 40. Each sliding member 41 has a taper upper end portion 41a. An opening 42 (Fig. 16) is formed in a side wall 3a of a journal box 3, and a vibration isolating unit 43 for the sliding member 41 is fitted in the opening 42. The vibration isolating unit 43 comprises a box 44 detachably fitted in the opening 42, a rubber vibration isolator 45 and a liner 46 fixed to the rubber vibration isolator 45. The box 44 is provided with a recess opening into the journal box 3, and the rubber vibration isolator 45 is fastened to three surfaces defining the recess of the box 44. A sliding groove 47 is formed in the side wall 3a of the journal box 3 so as to extend into the recess of the box 44. The upper end of the sliding groove 47 opens into the recess of the box 44. The sliding member 41 is fitted slidably in the sliding groove 47 so that the taper upper end portion 41a of the sliding member 41 is in contact with the liner 46 of the vibration isolating unit 43. As shown in Fig. 16, the upper surface 42a and the lower surface 42b of the opening 42 serve as an upper stopping surface and a lower stopping surface for the vibration isolating unit 43. The operation of the second embodiment will be described hereinafter on an assumption that the railroad car travels from the narrow-track rails 21 of the narrow track to the standard-track rails 22 of the standard track. The variable-wheel-gauge bogie is in the geometry shown in Figs. 8, 12, 14 and 15 while the railroad car is traveling on the narrow-track rails 21 and the conical locking projections 15A are fitted in the locking holes 16, respectively. Drive motors, not shown, drive the wheels 9 to drive the railroad car for traveling. Immediately after the variable-wheel-gauge bogie has entered the down sloping section L of the narrow-track rails 21, the sliding surfaces 3a of the journal boxes 3 come into contact with the car support rails 26, and then the journal boxes 3 are kept in a substantially horizontal plane by the car support rails 26 while the axles 4 and the axle sleeves 7 move downward relative to the journal boxes 3 according to the inclination of the down sloping section L. Consequently, the sliding members 41 shown in Figs. 14 to 16 move downward along the sliding grooves 47, and the conical locking projections 15A shown in Figs. 8 and 12 come off the corresponding locking holes 32 to allow the axle sleeves 7 to move axially. The axle sleeves 7 are allowed to move axially before the variable-wheel-gauge bogie reaches the terminal end of the down sloping section L at the latest. Then, the variable-wheel-gauge bogie starts traveling on the wheel gauge changing rails 23 of the wheel gauge changing track gradually widening toward the standard track. Then, the wheels 9 are guided by the guide rails 24 biased toward the wheels 9 by the springs 25 as the wheels roll on the wheel gauge changing rails 23, so that the wheels 9 are shifted gradually outward together with the associated axle sleeves 7 on the axles 4. When the variable-wheel-gauge bogie arrives at the terminal end of the wheel gauge chang-ing rails 23, the outer ends of the sleeves 7 come into contact with the corresponding stoppers 40, and the axle sleeves 7 are stopped. In this state, the distance between the pair of wheels 9 on each axle 4 is equal to the standard rail gauge, and the locking projections 15B are located opposite to the locking holes 32, respectively. Since the truck frame of the variable-wheel-gauge bogie is supported through the journal boxes 3 on the car support rails 26 while the variable-wheel-gauge bogie is traveling on the wheel gauge changing rails 23 or on sections of the narrow-track rails 21 or the standard track rails 22 near the ends of the wheel gauge changing rails 23, the wheels 9 and the axle sleeves 7 are lightly loaded, and hence the axle sleeves 7 are able to slide lightly along the axles 4 according to the variation of the rail gauge of the wheel gauge changing track. Then, the variable-wheel-gauge bogie moves from the wheel gauge changing rails 23 to the standard-track rails 22. While the variable-wheel-gauge bogie is traveling in the up sloping section L of the standard-track rails 22, the axles 4 and the axle sleeves 7 move upward relative to the journal boxes 3, the sliding members 41 shown in Figs. 14 to 16 slide upward along the sliding grooves 47, the conical head portions 15b of the conical locking projections 15B enter the vibration isolating units 43, respectively, the conical locking projections 15B are fitted in the locking holes 32 of the journal boxes 3, respectively, and the conical locking projections 15A enter the escape holes 33. Referring to Fig. 12, when the conical locking projection 15B enters the corresponding locking hole 32, the conical head portion 15b of the conical locking projection 15B passes the lower section 32a of the locking hole 32 and enters the upper section 32b, and the conical surface of the conical head portion 15b comes into contact with the inner ring 36 of the vibration isolating unit 34 to push the inner ring 36 up. Consequently, the rubber vibration isolator 37 is compressed and the large resilience of the compressed rubber vibration isolator 37 acts on the side surface of the conical locking projection 15B. The mode of engagement of the taper upper end portion 41a of the sliding member 41 with the vibration isolating unit 43 is similar to that of engagement of the conical head portion 15b of the conical locking projection 15B with the vibration isolating unit 34; the taper upper end portion 41a pushes the liner 46 up as the same moves up to compress the rubber vibration isolator 45. Since the conical locking projection 15B has the conical head portion 15b, the conical locking projection 15B can be surely fitted in the locking hole 32 even if the conical locking projection 15B and the locking hole 32 are dislocated slightly relative to each other. Thus, the axle sleeve 7 is restrained from axial sliding movement and the distance between the pair of wheels 9 on each axle 4 is fixed at the standard gauge. Since the conical locking projection 15B is fitted in the locking hole 32 by the weigh of the truck frame, the conical locking projection 15B will never come off the locking hole 32 accidentally. Since dynamic shocks due to the play of the conical locking projection 15B in the locking hole 32 during traveling are absorbed by the rubber vibration isolator 37, the abrasion of the component parts can be effectively prevented and high traveling stability can be secured. Particularly, since the rubber vibration isolator 37 is deformed elastically beforehand when the conical locking projection 15B is fitted in the locking hole 32, the dynamic shocks that occur during travel due to the play can be very effectively absorbed, and the relative movement of the journal box 3 and the axle sleeve 7 can be effectively suppressed. Since the cylindrical lower portion 15a of the conical locking projection 15B is received in the lower section 32a of the locking hole 32 having a diameter substantially equal to that of the cylindrical lower portion 15a when the conical locking projection 15B is fitted in the locking hole 32, the area of contact between the surface of the cylindrical lower portion 15a and the side surface of the lower section 32a is comparatively large, which is advantageous in strength. There is the possibility, due to some causes, that the conical head portion 15b of the conical locking projection 15B bites the inner ring 36 of the vibration isolating unit 34 and deforms the rubber vibration isolator 37 excessively when the conical locking projection 15B moves into or when the same moves out of the locking hole 32. This embodiment uses the inner flange 35a of the outer ring 35 disposed above the rubber vibration isolator 37 as an upper stopper, and a portion of the journal box 3 under the rubber vibration isolator 37 as a lower stopper to prevent the excessive deformation of the rubber vibration isolator 37. Since the sliding member 41 projecting from the end stopper 40 is fitted in the sliding groove 47 formed in the journal box 3 and the vibration isolating unit 43, the journal box 3 and the axle 4 are maintained in a fixed positional relation and hence the positional relation between the locking hole 32 of the journal box 3 and the axle 4 is fixed. Accordingly, the conical locking projection 15 fixed to the axle sleeve 7 can be surely fitted in the locking hole 32. The operation of the second embodiment when the railroad car travels from the standard-track rails 22 of the standard track to the narrow-track rails 21 of the narrow track is reverse to the foregoing operation of the same-and hence the description of the former will be omitted. Although the entire length of the car support rails 26 is extended in a horizontal plane and the sloping sections L are formed in sections of the narrow-gauge track and the standard-gauge track continuous with the wheel gauge changing rails 23 of the wheel gauge changing track in this embodiment, the respective rails 21, 22 and 23 of the narrow-gauge track, the standard-gauge track and the wheel gauge changing track may be extended in a horizontal plane and sloping sections may be formed in the car support rails 26. Since the wheels 9 are guided by the guide rails 24 biased by the springs 25 so as to be in contact with the side surfaces of the wheels 9, the wheels 9 can be very smoothly shifted according to the variation of the rail gauge of the wheel gauge changing track for wheel gauge adjustment. Fig. 18 shows vibration isolating unit 34 for conical locking projection, in a modification. The vibration isolating unit 34 shown in Fig. 18 has an annular plate spring 51 having a V-shaped section and set along the circumference of the locking hole 32. The plate spring 51 has a flange 51a detachably fastened to the journal box 3 with screws 52. Longitudinal slits 53 are formed in the annular plate spring 51, and a recess 54 is formed in the circumference of the locking hole 32 to allow the elastic deformation of the annular plate spring 51. The annular plate spring 51, similarly to the rubber vibration isolator 37 shown in Fig. 12, is elastically deformed by the conical locking projection 15 and applies its resilience to the conical locking projection 15. The vibration isolating unit 34 employing the annular plate spring 51 is simpler in construction than the vibration isolating unit 34 shown in Fig. 12, can be easily fabricated and assembled, and is superior in durability to the vibration isolating unit 34 shown in Fig. 12. Fig. 19 shows a vibration isolating unit 34 for conical locking projection, in another modification. The vibration isolating unit shown in Fig. 19 comprises a wedge ring 57 fixedly fitted in the upper section of the locking hole 32, a cover 55 detachably fastened to the journal box 3 with screws 56 so as to cover the upper open end of the upper section of the locking hole 32, and a Belleville spring 58 disposed between the upper surface of the wedge ring 57 and the cover 55 to bias the wedge ring 57 downward. Since the Belleville spring 58 is a means simply for biasing the wedge ring 57 downward, the same may be substituted by an elastic rubber ring. The conical portion of the conical locking projection 15 comes into engagement with the inner circumference of the wedge ring 57 when the conical locking projection 15 is fitted in the locking hole, and the wedge ring 57 biased downward by the Belleville spring 58 comes into close contact with the conical locking projection 15 by its own wedging action. Thus, the conical locking projection 15 can be held in the locking hole 32 substantially without any play. The wedge ring 57 is provided with a slit 59 as shown in Fig. 20 in order that the wedge ring 57 can be elastically distorted and easily fitted in the locking hole 32. Figs. 21 and 22 show vibration isolating unit 43 for sliding member, in a modification. This vibration isolating unit 43 comprises a cover 61 detachably attached to the side surface of the journal box 3 so as to cover an opening 60 formed in the side wall of the journal box 3, and a U-shaped spring plate 62 having a V-shaped cross section as shown in Fig. 22 and fitted in the opening 60. A recess 63 similar to the recess 54 (Fig. 18) is formed in the opening 60. The operation of the vibration isolating unit 43 for sliding member, employing the plate spring 62 is substantially the same as that of the vibration isolating unit 34 for conical locking projection. Figs. 23 and 24 show modifications of the sliding member 41 and the guide cavity. Brackets 65 projects from the opposite ends of the end stopper 40, respectively, a sliding pin 66 is set in an upright position on each bracket 65. The upper end portion of the sliding pin 66 is tapered in a conical shape. Guiding through holes 67 are formed in the journal box 3 to guide the sliding pins 66 for vertical movement. A vibration isolating unit 68 for sliding member is disposed in an upper portion of the through hole 67. The vibration isolating unit 68 is entirely the same in construction as the vibration isolating unit 43 for conical locking projection, shown in Fig. 12; the vibration isolating unit 68 comprises an outer ring, a rubber vibration isolator and an inner ring. Naturally, the vibration isolating unit 68 for sliding member may employ a plate spring having a V-shaped cross section similar to the plate spring 51 shown in Fig. 18. While the presently preferred embodiments of the present invention have been shown and described, it is to be understood that these disclosures are for the purpose of illustration and that various changes and modifications may be made without departing from the scope of the invention as set forth in the appended claims.

Claims: A system for changing the gauge of a rolling stock bogie having, a pair of side beams (1) for supporting wheel axles (4) on a rail road via wheels (9), journal boxes (3) provided under said side beams (1), respectively, to receive ends of said wheel axles (4), and axle sleeves (7) rotably supporting said wheels (9) thereon and fitted on said wheel axles (4) slidably along the wheel axles, respectively, comprising: first engagement means (15A, 15B) formed on an outer peripheral surface of each of said axle sleeves (7); second engagement means (16, 17) formed on an inside surface of each of said journal boxes (3) and provided to selectively engage said first engagement means (15A, 15B) when said wheels (9) are positioned to match one of different gauges; wheel gauge changing rails (23) laid between two rails (21, 22) of different gauges and provided to allow said rolling stock bogie to roll thereon; and car support rails (26, 27) provided in parallel with said wheel gauge changing rails (23) to separate the rolling stock bogie from said sleeves (7) and said wheels (9) in a vertical direction to disengage said second engagement means (16, 17) from said first engagement means (15A, 15B) while said rolling stock bogie rolls on said wheel gauge changing rails (23) so as to change said gauge without stopping the rolling stock bogie; characterized by: a fastening device (18) for fastening together each of said journal boxes (3) and each of said wheel axles (4) to restrain the journal boxes from vertical movement relative to the wheel axles and to release the journal boxes from the wheel axles before the rolling stock bogie starts traveling on the wheel gauge changing rails (23). The system for changing the gauge of a rolling stock bogie according to claim 1, characterised by comprising: a drive motor (10) for each of the wheels (9), having a stator (10a) formed on the outer peripheral surface of each of said axle sleeves (7). The system according to claim 1 or 2, characterised in that each axle (4) is provided with annular grooves (6) in its end portions, respectively, each journal box (3) has an extension (17) fitted in each annular groove of the axle, each fastening device (18) has wedging members (18a) held adjacent to the extension so as to be forced into the annular groove (6) of the axle, and wedge biasing members (20) for biasing the wedge members toward each annular groove, the wedging members (18a) presses the extension (17) against the side surface of each of the annular grooves (6) by its wedge action when forced into the annular groove of the axle to fasten together the journal box and the axle. The system according to claim 3, characterised in that each car support rail (26) has a wedge guide rail (27) transversely projecting therefrom and capable of retracting the wedge members (18a) from the annular groove (6) of the axle (4) against the biasing force of the wedge biasing members (20) to disengage the journal box (3) from the axle (4). The system according to claim 1 or 2, characterised in that the wheel gauge changing rails (23) further comprises guide rails (24) extending on both sides of and along the wheel gauge changing rails (23) and to come into contact with the side surfaces of the wheels (9), and biasing members (25) for biasing the guide rails (24) to bring the guide rails into contact with the side surfaces of the wheels (9). The system according to claim 1 or 2, characterised in that each journal box (3) is provided with shims (50) for thickness adjustment on its lower surface that come into contact with the car support rail (26). A variable-wheel-gauge bogie of rolling stock, for automatically changing its wheel gauge while traveling on wheel gauge changing rails (23) interconnecting rails of a broad-gauge track of a broad rail gauge and rails of a narrow-gauge track of a narrow rail gauge, said variable-wheel-gauge bogie comprising: journal boxes (3) suspended from side beams (1) of a truck frame by elastic members (2), respectively; axles (4) vertically movably supported on the journal boxes (3); an axle sleeve (7) axially slidably fitted on each of the axles (4) for movement between a position for the broad rail gauge and a position for the narrow rail gauge; wheels (9) supported for rotation on the axle sleeves (7), respectively; drive motors (10) for driving the wheels (9) in rotation, supported on the axle sleeves (7), respectively; on-sleeve locking members (15A, 15B) formed on the outer circumferences of the axle sleeves (7), respectiverly; and an on-box locking means (16) formed on the journal boxes (3), for engaging with the on-sleeve locking members (15A, 15B), respectively, to restrain the axle sleeves (7) from axial movement when each of the axle sleeves is at a position for the broad rail gauge or at a position for the narrow rail gauge, and when the weight of the truck frame acts thereon through the journal boxes (3): characterised by: fastening devices (18) each for fastening together the journal box (3) and the corresponding axle (4) to restrain the journal box from vertical movement relative to the axle sleeve (7), and for disengaging the journal box (3) from the axle (4) immediately before the variable-wheel-gauge bogie starts travelling on the wheel gauge changing rails (23); and by car support units (3a) each formed on the lower surface of each journal box (3) to support the body of the bogie when changing the wheel gauge. A variable-wheel-gauge bogie of rolling stock, for automatically changing wheel guage while a railroad car is traveling on wheel gauge changing rails (23) interconnecting rails of a broad-gauge track of a broad gauge and rails of a narrow-gauge track of a narrow gauge, said variable-wheel-gauge bogie comprising: pairs of journal boxes (3) suspended from side beams (1) of a truck frame by elastic members (2), and provided with locking means (32) in their upper walls, respectively; car support units (3a) each formed on the lower surface of each journal box (3) to support the body of a railroad car when changing the wheel gauge; axles (4) vertically movably supported on the journal boxes (3) with the opposite ends thereof contained in the journal boxes, respectively; pairs of axle sleeves (7) axially slidably fitted on the axles (4), respectively, for movement between a position for the broad rail gauge and a position for the narrow rail gauge; pairs of wheels (9) supported for rotation on the pairs of axle sleeves (7), respectively; pairs of locking blocks (13) attached to the outer circumferences of the pairs of axle sleeves (7), respectively, and each having an upper surface for bearing the weight of the railroad car through the journal box (3); and locking projections (15A, 15B) projecting from the upper surface of each locking block (13) so as to be engaged with the locking means (32) of the journal boxes when the axle sleeve (7) is at a position for the broad rail gauge or the narrow rail gauge; characterised in that: said locking means (32) are locking holes formed in the upper walls of the journal boxes (3) so as to allow fitting engagement of the locking projections (15) therein; in that each of the locking projections (15) is a conical projection having a lower cylindrical portion (15a) of a substantially fixed diameter and a predetermined height, and an upper taper conical portion (15b); in that each of the locking holes (32) has a lower section (32a) of a diameter substantially equal to that of the cylindrical portion (15a) of the conical locking projection, and an upper section (32b) of a diameter greater than that of the lower section (32a); and in that vibration isolating units (37) are each provided in each of the locking holes (32) so as to surround the taper conical portion (15b) to be in elastic contact with the conical portion. The variable-wheel-gauge bogie according to claim 8, characterised by: central stoppers (5) each projecting from a middle portion of each axle (4) to restrain the axle sleeve (7) from moving beyond the position for the narrow rail gauge toward the middle of the axle; end stoppers (40) projecting from opposite end portions of each axle (4) to restrain the axle sleeves (7) from moving beyond the positions for the broad rail gauge toward the ends of the axle; sliding member (41) projecting from both sides of each end stopper (40) and each having a taper upper end portion (41a); guide cavities formed in each journal box (3) to guide the sliding members (41) for vertical movement, respectively; and vibration isolating units (43) each disposed in an upper portion of each guide cavity so as to be in elastic contact with the surface of the taper upper end portion (41a) of the sliding member. The variable-wheel-gauge bogie according to claim 8 or 9, characterised in that the vibration isolating unit (34) for locking projection comprises an outer ring (35) fixedly fitted in the upper section (32b) of the locking hole (32), an elastic vibration isolator (37) fixed to the inside surface of the outer ring (35), and an inner ring (36) fixed to the inside surface of the vibration isolator, and the inner ring (36) is moved by the conical portion (15b) of the conical locking projection (15) to deform the vibration isolator (37) when the conical locking projection is fitted in the locking hole. The variable-wheel-gauge bogie according to claim 8 or 9, characterised in that the vibration isolating unit (34) for locking projection has an annular plate spring (51) having a V-shaped section. The variable-wheel-gauge bogie according to claim 8 or 9, wherein the vibration isolating unit for locking projection comprises an outer ring (57) fitted in the upper section of the locking hole, a cover (55) covering the upper open end of the upper section of the locking hole, and an elastic member (58) disposed between the upper surface of the wedge ring (57) and the cover (55) to bias the wedge ring downward, and the conical portion of the conical locking projection (15) comes into engagement with the inner circumference of the wedge ring (57) when the conical locking projection (15) is fitted in the locking hole. The variable-wheel-gauge bogie according to claim 9, characterised in that the sliding member (41) are outward extensions of the opposite side surfaces of the end stopper (40), and the guide cavities are sliding grooves (47) formed in the opposite side walls of the journal box (3). The variable-wheel-gauge bogie according to claim 13, characterised in that the vibration isolating unit (43) for sliding member (41) comprises a box (44) fitted in an opening formed in each side wall of the journal box (3), detachably attached to the side wall and having a recess opening into the interior of the journal box, an elastic vibration isolator (45) attached to the surface of the recess of the box (44), and a liner (46) fixed to the vibration isolator (45) so as to be in contact with the taper upper end portion (41a) of the sliding member (41). The variable-wheel-gauge bogie according to claim 13, characterised in that the vibration isolating unit (43) for the sliding member (41) has a plate spring having a V-shaped cross section and in elastic contact with the end surface of the taper upper end portion (41a) and the opposite side surfaces of the sliding member (41). The variable-wheel-gauge bogie according to claim 9, characterised in that the sliding amembers are pins (66) projecting upward from brackets (65) projecting from the opposite side surfaces of the end stopper (40), and the guide cavities (67) are vertical through holes formed in the journal box (3). The variable-wheel-gauge bogie according to claim 16, characterised in that the vibration isolating unit for the sliding member (41) comprises an outer ring (35) fixedly disposed in the upper portion of the guide cavity, an elastic vibration isolator (37) fixed to the inside surface of the outer ring (35), and an inner ring (36) fixed to the inside surface of the vibration isolator, and the inner ring (36) is moved by the taper upper end portion (41a) of the sliding member so as to deform the elastic vibration isolator (37) when the sliding member is inserted in the guide cavity.

Inventors: AOKI TSUNEO, MINOWA YUKIO, OGAWARA MASAO, TOKUDA NORIAKI, WAKO KANJI, WATANABE TERUHIDE, AOKI, TSUNEO, MINOWA, YUKIO, OGAWARA,MASAO, TOKUDA, NORIAKI, WAKO, KANJI, WATANABE, TERUHIDE, Ogawara,Masao c/o JP Railway Constr.Publ.Corp.
Applicants: FUJI HEAVY IND LTD, JAPAN RAILWAY CONSTRUCTION PUB, RAILWAY TECHNICAL RES INST, FUJI JUKOGYO KABUSHIKI KAISHA, JAPAN RAILWAY CONSTRUCTION PUBLIC CORPORATION, RAILWAY TECHNICAL RESEARCH INSTITUTE
Application year: 1996
Main classification: B61F7
IPC codes: B61H9, B60B35, B61F7