Abstract:
A front end portion  100  is disposed on the front end of a car body. The floor thereof consists of hollow shape members  200  that construct a shock absorber  200.  The shock absorber  200  includes an upper shock absorber  200  and a lower shock absorber  200.  Annealed hollow shape members are used to form the hollow shape member  210.  The hollow shape members  210  have their longitudinal directions disposed along the longitudinal directions of the car body. Plural hollow shape members  210  are arranged next to one another in the width direction, and bonded together by friction stir welding. When the hollow shape members receive impact load, the members  210  deform into an accordion-like shape, absorbing the impact force. At this time, the friction stir welded portions also receive the impact force, but dislike other weld joints, cracks are not created at the friction-stir-weld joints, and the weld joints do not prevent the hollow shape members  210  from deforming into an accordion-like shape.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a body of a railway car that travels on rails, and is especially preferable for forming a railway car body using hollow shape members made of light alloy.  
         DESCRIPTION OF THE RELATED ART  
         [0002]    In forming a railway car, it is required to consider applying means for absorbing and easing the impact force loaded to the passengers on board when collision occurs. Japanese Patent Laid-Open Publication No. H7-186951 (U.S. Pat. No. 5,715,757) discloses absorbing the energy generated by the impact of the collision to the front end of the leading car by the deformation thereof. This reliever comprises triangular elements and honeycomb panels disposed within a plane perpendicular to the direction of impact, and has various designs. A plural number of relievers is positioned either in parallel relations against the direction of impact or linearly along the direction of impact.  
           [0003]    A welding method called a friction stir welding method is proposed as a means to weld members, and this method is also applied to forming railway cars. This method is disclosed in Japanese Patent No. 3014654 (EP 0797043 A2).  
           [0004]    According to the disclosure of Japanese Patent Laid-Open Publication No. H11-51103, when friction stir welding is performed to members, the metal constitution of the friction-stir-welded portion becomes refined, and the energy absorption rate is improved.  
           [0005]    In the disclosure, friction stir welding is performed in a ring-like or spiral-like manner to the extruded hollow shape member made of aluminum alloy, and the welded member is used as the steering shaft of an automobile. Friction stir welding is performed in the direction perpendicular to the direction of the impact energy, and the friction-stir-welded portion absorbs the impact force. Moreover, a plurality of short pipe-like members is arranged linearly along the direction of impact energy, and the members are friction-stir-welded so as to form a shaft.  
         SUMMARY OF THE INVENTION  
         [0006]    The above-mentioned Japanese Patent Laid-open Publication No. H7-186951 (U.S. Pat. No. 5,715,757) proposes a reliever to be mounted on a railway car that is meant to absorb the impact of collision. This reliever comprises plural relieving devices, thereby realizing the safety of the passengers on board.  
           [0007]    Since the reliever is mounted on the railway car body, the length of the reliever should preferably be short so as to secure space for the passengers.  
           [0008]    The present invention aims at providing a railway car that is capable of absorbing the impact energy.  
           [0009]    The above object can be achieved by a railway car characterized in that:  
           [0010]    a member constituting the floor at an end portion of the car body is a shock absorber;  
           [0011]    the shock absorber comprises plural extruded shape members having hollow portions;  
           [0012]    the hollow extruded shape members include plural hollow portions arranged along the width direction of the car body;  
           [0013]    the hollow extruded shape members are disposed so that the direction of extrusion thereof is disposed along the longitudinal direction of the car body;  
           [0014]    the hollow shape members are opposed to the underframe of said car body; wherein  
           [0015]    the shock absorber is disposed as upper and lower layers,  
           [0016]    or by providing no hollow shape member to the region equipped with the shock absorber corresponding to side sills provided to other regions,  
           [0017]    or by not connecting the coupler for coupling cars together with the shock absorber,  
           [0018]    or by increasing the number or the vertical cross-sectional area of the shock absorbers provided to the leading car compared to the number or the vertical cross-sectional area of the shock absorbers provided to the middle cars.  
           [0019]    Moreover, the object of the present invention can be achieved by a car formation comprising plural car bodies being connected;  
           [0020]    a member supporting the floor at an end portion of each of said car bodies is a shock absorber; wherein  
           [0021]    an entrance or a control panel is positioned above the shock absorber, or  
           [0022]    the vertical cross-sectional area of the shock absorber near the leading car is greater than the vertical cross-sectional area of the shock absorber equipped in the middle cars. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 is a side view showing the car formation of the railway car according to one embodiment of the present invention;  
         [0024]    [0024]FIG. 2 is a side view showing the state in which the front end portion of FIG. 1 is separated;  
         [0025]    [0025]FIG. 3 is a plan view showing the front end portion of FIG. 2;  
         [0026]    [0026]FIG. 4 is a left side view of FIG. 2;  
         [0027]    [0027]FIG. 5 is a V-V cross-sectional view of FIG. 3;  
         [0028]    [0028]FIG. 6 is a VI-VI cross-sectional view of FIG. 4;  
         [0029]    [0029]FIG. 7 is a VII-VII cross-sectional view of FIG. 6;  
         [0030]    [0030]FIG. 8 is a VIII-VIII cross-sectional view of FIG. 6;  
         [0031]    [0031]FIG. 9 is a drawing showing the method of welding the shock absorber of FIG. 1;  
         [0032]    [0032]FIG. 10 is an explanatory view showing the impact energy of the material; and  
         [0033]    [0033]FIG. 11 is a stress-flexure diagram of the materials. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0034]    One embodiment of the present invention will now be explained with reference to FIGS. 1 through 9. In FIG. 1 and FIG. 2, the leading portion is separated from the car body so that the present invention can be understood more easily.  
         [0035]    The present car formation comprises two leading cars A that are disposed at the front and back ends of the car formation, and middle cars B, the number of which varies according to need. A front end portion  100  of the leading car A is curved and projected in an arc-like shape toward the forward direction. A shock absorber  200  is mounted to the front end portion  100 . Further, shock absorbers  400 ,  400  are respectively arranged between the rear end (other end) of each leading car body A and the end of the middle car B adjacent thereto. First, the shock absorber  200  mounted to the front end portion  100  will be explained in detail.  
         [0036]    A car body  90  excluding the front end portion  100  comprises side structures  10  that constitute the sides of the car body, the roof structure  20 , an underframe  30  that constitutes the floor thereof, and so on. The side structures  10 , the roof structure  20 , and the underframe  30  are all formed by welding plural hollow shape members together. Each hollow shape member is an extruded shape member made of light alloy (such as aluminum alloy), and the direction of extrusion (that is, the longitudinal direction) is arranged along the longitudinal direction of the car body. Plural hollow shape members are arranged along the circumference direction of the car body with the width direction of the members positioned adjacent to each other, and the members are welded to form a single structure. At the end of the car body  90  is provided a seat  40  for fixing the front end portion  100 . The space  80  provided at the forward end of the car body  90  is the driver&#39;s cab, and a driver&#39;s seat  85  is mounted to the floor formed above the underframe  30 .  
         [0037]    The front end portion  100  comprises a frame  110  for locking the portion to the car body, plural pillars  120 ,  130 , plural cross beams  140 , a shock absorber  200 , an anticlimber  250 , and so on. The frame  110  has four sides, and the upper side is U-shaped. The frame  110  is removably fixed to the seat  40  of the car body  90  by bolts. The pillars  120  connect the upper end of the frame  110  and the front end of the shock absorber  200 . The pillars  120  are positioned near the center of the car body when seen from the front of the body. The pillars  120  are disposed on both sides of a coupler  70 . The pillars  130  connect the upper portion of the frame  110  and the sides of the shock absorber  200 . The pillars  130  are placed at the center portion in the longitudinal direction of the shock absorber  200 , and is connected to both side surfaces of the car body. Since the pillars  120  are likely to collide against obstacles, they are designed to be larger and stronger than the pillars  130 . The cross beam  140  is disposed at the center of height of the frame  110  and connects the frame  110  and the pillars  130 ,  120 . These connecting portions are welded together. The area composed of the frame  110 , the pillars  120  and  130 , and the cross beam  140  is covered smoothly by plates or glass material (not shown).  
         [0038]    The rear end of the shock absorber  200  is abutted against and welded to the lower edge of the frame  110 . The shock absorber  200  is composed of two layers, an upper layer and a lower layer. The lower portion of the shock absorber  200  is welded onto a seat  115  arrange in parallel therewith at a position below the lower edge of the frame  110 . The seat  115  is welded onto the lower edge of the frame  110 .  
         [0039]    The side structure  10 , the roof structure  20 , and the underframe  30  are made by welding plural hollow extruded shape members made of light alloy (such as aluminum alloy). Especially, the underframe  30  is formed strongly. The lower edge of the seat  40  is designed to have the same shape as the seat  115 . The back surface of the seat  40  and the lower surface of the underframe  30  are connected strongly by plural stays  45 .  
         [0040]    The upper shock absorber  200  is opposed to the seat  40  of the underframe  30  through the lower edge of the frame  110 . The lower shock absorber  200  is opposed to the lower portion of the seat  40  of the underframe  30  through the seat  115 .  
         [0041]    The front end of the upper and lower shock absorbers  200 ,  200  is welded onto an anticlimber  250 . The front end of the anticlimber  250  has projections and recesses, preventing the obstacle that collides against the body from moving upward. A rubber shock absorbing unit is mounted between the front end of the anticlimber  250  and the shock absorbers  200 ,  200 .  
         [0042]    The shock absorber  200  is not only designed to have two (upper and lower) layers, but is also divided into left and right portions when observed from the front of the car body. The space between the left and right shock absorbers  200 ,  200  of the lower layer constitutes the space through which the coupler  70  of the car passes. The upper shock absorbers  200 ,  200  also have a space formed therebetween, the upper portion of which mounting a plate  150  that is used as the floor for mounting equipment. The plate  150  is fixed to the upper shock absorbers  200 ,  200 . Further, the plate  150  is mounted on a support seat  151  fixed to the upper shock absorbers  200 ,  200 . There are plural support seats  151  at predetermined intervals along the longitudinal direction of the car body. The plate  150  can cover the whole surface of the shock absorbers  200 ,  200 .  
         [0043]    Moreover, it is also possible to place a shock absorber between the two upper layer shock absorbers  200 ,  200 , being integrally formed with the left and right shock absorbers  200 ,  200 . In this case, there is no need to provide the plate  150  and support seats  151 . Moreover, the anticlimber  250  can be mounted on the front end side of the added shock absorber  200 .  
         [0044]    The shock absorber  200  comprises a hollow extruded shape member  210  made of light alloy (such as aluminum alloy). The hollow shape member  210  is arranged so that the direction of extrusion thereof is arranged along the direction of travel (the longitudinal direction) of the car body. The hollow portion is oriented along the longitudinal direction. A plurality of hollow shape members  210 ,  210  are assembled along the width direction of the car body. The width-direction-ends of the hollow shape members  210  are welded to one another. Each shock absorber  200  comprises two hollow shape members.  
         [0045]    The hollow shape member  210  comprises two face plates  211  and  212 , connecting plates  213  connecting the two face plates and being slanted against the two face plates  211  and  212 , and a connecting plate  215  substantially orthogonal to the face plates  211  and  212  disposed at the width-direction-end thereof. The face plates  211 ,  212  and the connecting plates  213  constitute trusses. The connecting plate  215  is disposed to one of the two hollow shape members at the joint between the two members.  
         [0046]    The hollow shape members  210  are welded together by friction stir welding. The welding direction is along the longitudinal direction thereof. A segment  216  protrudes toward the end side at the joint between the face plate  211  ( 212 ) and the connecting plate  215 . The end side portion of the connecting plate  215  is recessed than the outer surface of the face plates  211 ,  212 . The projecting segment  216  is formed to this recessed position. The face plates  211 ,  212  of the other hollow shape member  210  overlap with the recessed portion. The face plates  211  and  212  of the two hollow shape members are each abutted against the corresponding face plate, respectively. The end surface of the face plates  211 ,  212  of the hollow shape member  210  where the connecting plate  215  is formed (the surface including the recessed portion) is substantially disposed on the extension of the center of plate thickness of the connecting plate  215 . The outer surfaces at the end of face plates  211  and  212  being abutted against the other hollow shape member are provided with projections  217  that protrude in the thickness direction of the hollow shape member. The projections  217  on the two hollow shape members are also abutted against one another.  
         [0047]    Friction stir welding will now be explained. One pair of hollow shape members  210 ,  210  is mounted on a bed  300 . The lower projections  217 ,  217  of the members are mounted on the bed  300 . The butt joint is temporarily welded by arc welding along the longitudinal direction thereof. The upper abutted portion is friction-stir-welded using a rotary tool  310 . The lower end of a large-diameter portion of the rotary tool  310  is positioned between the outer surface of the face plate  211  ( 212 ) and the apex of the projections  217 ,  217 . The remaining projection can be removed if necessary by cutting. After friction-stir-welding the upper portion, the hollow shape members  210 ,  210  are turned up-side down, and friction stir welding is performed to the opposite side in a similar manner. The projections  217  can be omitted.  
         [0048]    The hollow shape member  210  is for example a member for forming the underframe  30 . One or more hollow shape members are used to form the necessary width of the shock absorber  200  (the width direction of the car body). If necessary, the width of the hollow shape member can be cut off. It is best that the with direction of the shock absorber  200  is flat, so the hollow shape member for the underframe  30  is preferred. However, the side sill of the underframe  30  will not be used. Further, the side structure  10  also includes linear hollow shape members, which can also be used as the present shock absorber. The cost of the shock absorber is inexpensive since the hollow shape members for forming the other parts of the car body can be applied.  
         [0049]    The hollow shape member  210  of the shock absorber  200  is softer than the hollow shape members constituting the underframe  30 , the side structures  10 , or the roof structure  20 , and can easily collapse during collision, thereby absorbing the energy of the impact. The hollow shape member  120  is formed by annealing and softening the hollow shape member used to create the underframe.  
         [0050]    The annealing can be, for example, an O-material treatment (temper of annealed metal). In general, various heat treatments are provided to the extruded member after the extrusion. If the material of the extruded member is A6N01, an artificial aging and hardening process of T 5  is performed. The annealing of the O-material is performed thereafter. The annealing treatment to the O-material is performed for two hours at 380° C., and the strength is 36.8 MPa. T5 has a strength of 245 MPa. The annealing of the O-material is meant to soften the material as the hollow shape member. The elongation of the hollow shape member  210  is greater than that of the general hollow shape member. The strength of the hollow shape member  210  is smaller than that of the general hollow shape member. In order to provide necessary strength and softness to the member, annealing other than the O-material can also be performed. Further, the plate thickness of the hollow shape member can also be chosen to provide the best performance.  
         [0051]    The lowermost end of the pillars  120  and  130  are welded to the upper and lower hollow shape members  210 ,  210 . Welding is performed by forming notches to the upper and lower hollow shape members  210  having a shape corresponding to the pillars  120  and  130 , and then welding the members. The width-direction-ends of the upper and lower hollow shape members  210 ,  210  are welded to plural members  250 .  
         [0052]    The surface of the anticlimber  250  facing the hollow shape members  210  is provided with plural pipes  256 , which are inserted to the plural hollow portions of the hollow shape members  210 . The outer diameter of each pipe  256  is substantially equal to the inscribing circle of the hollow portion having a triangular cross-section. The pipes  256  are inserted to every other triangular hollow shape portion. The pipes  256  are welded onto the seat  253  of the anticlimber  250  while being inserted to the holes formed to the seat  253 . The frame  110  and the seat  115  also have pipes  256 , which are inserted to the hollow portion of the hollow shape member  210 .  
         [0053]    The upper half of the front end portion  100  is provided with windows and the like, and the lower front end space thereof stores equipment for operating the railway car. The lower end of the plates constituting the side surfaces of the front end portion  100  covers the sides of the upper and lower shock absorbers  200 ,  200 .  
         [0054]    In the underframe  30 , side sills (not shown) are provided to both width-direction-ends of the car body. The side sill is a large and firm hollow shape member. The front end portion  100  does not have hollow shape members corresponding to the size of the side sill. Further, the front end portion  100  does not include a member having the strength corresponding to that of the hollow shape member forming the side sill of the underframe  30 . A member (not shown) for connecting the coupler  70  is equipped to the lower surface of the underframe  30 . However, the front end portion  100  is not equipped with such member. This member is equipped along both the longitudinal direction and the width direction of the car body. This member and the hollow shape member constituting the side sill is strong against the compressive load in the longitudinal direction of the car body. Moreover, there is also a member for supporting the coupler  70 .  
         [0055]    When the railway car crashes into an obstacle, impact load occurs. When the coupler  70  collides, the impact causes the coupler  70  to drop off from the car, and causes the shock absorber  200  to exert its shock absorbing function. When the anticlimber  250  collides, the impact acts on the hollow shape members  210  constituting the shock absorbers  200 ,  200 .  
         [0056]    Since the hollow shape members  210  are soft, they deform upon receiving impact before deformation of the underframe  30  occurs, thereby relieving the impact. According thereto, the safety of the passengers is ensured. The impact causes the length of the hollow shape members  210  to shrink to about half to one-third of their original length. At such time, the equipment provided above the hollow shape members  210  is prevented from entering the driver&#39;s cab and harming the driver. This is realized for example by appropriately designing the position and size of the equipment. Moreover, a partition wall for separating the equipment and the driver&#39;s cab  80  can be equipped to the frame  110 , the upper shock absorbers  200 ,  200  and the plate  150 , so as to ensure the safety of the driver. The partition wall can be constituted by the box enclosing the equipment. The partition wall can be equipped to the seat  40  and the underframe  30 . Moreover, the driver&#39;s seat  85  can be set to a position where it is clear of any equipment that may enter the driver&#39;s cabin upon impact. According to another example, sufficient space is provided between the seat  85  and the equipment that may enter the cabin.  
         [0057]    We will now explain the impact-relieving characteristic of the hollow shape member  120 . When compressive load is added thereto, the hollow shape member shows the load-deformation behavior as shown in FIG. 10. Three types of material characteristics is considered as shown in FIG. 11, a material i having high strength (such as pull strength, yield strength) and small elongation (brittle), a material iii having less strength but better elongation, and a material ii having a property intermediate those of materials i and iii. The material shown by the curve X (X 1 , X 2 ) of FIG. 10 (the material corresponding to strength property i of FIG. 11) has better withstand load, but the withstand load drops rapidly when the value exceeds the maximum load. On the other hand, when the material has low strength and high elongation (the material corresponding to strength property iii of FIG. 11), the maximum withstand load is smaller but the withstand load does not rapidly drop after the maximum value, as shown by the curved line Y of FIG. 10.  
         [0058]    The shaded area shown in FIG. 10 corresponding to curved line Y indicates the breaking energy of this material. When comparing the X curve with the Y curve, the material having less strength and more elongation (in this case, the material of curved line Y) has higher breaking energy according to the deformation behavior after exceeding the maximum withstand load. It is important to select as shock absorbing member B a material having such strength characteristic Y. A material having the Y-curve property can be obtained easily by providing an O-material treatment to an extruded member, for example.  
         [0059]    In case of the curved line X, since the material has high strength and small elongation, the elongation of the member cannot correspond to the imbalance of the stress within the cross-section of the member, causing partial breaking thereof, and reducing the withstand load rapidly. On the other hand, in the case of the curved line Y, the maximum withstand load of the member is lower than the material of the curve X, but since the elongation of the material is greater, plastic deformation of the material (elongation of the member) occurs partially corresponding to the scattered stress within the cross-section of the material, preventing the withstand load from dropping rapidly. According to this material, the material can deform greatly while maintaining a certain level of withstand load.  
         [0060]    When such material is utilized, the hollow shape member  210  deforms into a concertinas (into an accordion-form), relieving the shock loaded to the car body. Moreover, since a hollow-shape form is applied, in comparison to the general thin-plate structure, the member has higher inner-plate and outer-plate flexural rigidity, and since it has a composite structure including two face plates and cross (oblique) plates, it has higher breaking-energy absorption property against the compressive load (per unit planar area).  
         [0061]    Plural hollow shape members  210 ,  210  are welded together by friction stir welding along the longitudinal direction of the car body in the direction of the impact. If the welding is performed by arc welding, the weld portion may break during impact and the members cannot deform into an accordion form, and the energy absorption characteristic of the members drop. This is because by arc welding, the impact value of the weld portion is greatly reduced compared to the impact value of the base material. On the other hand, the impact value of the friction-stir-welded portion is higher compared to the arc-weld portion, and the joint will not break by impact. The reason for this is considered to be that the metal constitution of the joint is refined by the friction stir welding, and the energy absorption value is improved. Therefore, when the hollow shape members are welded by friction stir welding, each hollow shape member deforms in a desired manner, absorbing the impact energy.  
         [0062]    Since the shock absorbers  200  are provided in upper and lower layers, the impact energy can be absorbed by applying existing hollow shape members.  
         [0063]    The upper and lower hollow shape members  210  are notched in the form of pillars  120 ,  130 , so as to weld the pillars. According to this structure, the impact of the collision can be transmitted effectively to the hollow shape members  210 ,  210  from the pillars  1200 ,  130  that collide with an obstacle.  
         [0064]    Since the anticlimber  250  is overlapped with the hollow shape member  210  by its pipes  256 , the anticlimber  250  can transmit the impact to the hollow shape member  210  even when it collides slantwise against the obstacle.  
         [0065]    According to the above-mentioned embodiment, friction stir welding is performed from both sides of the hollow shape member, but it is also possible to weld the second face plates of two members from the first face plate side of the members, and then weld the first face plates via a connecting material, as shown in FIG. 9 of the above-mentioned Japanese Patent No. 3014654 (EP 079743 A2).  
         [0066]    Now, the shock absorber  400  mounted between the rear end of the leading car A and the end of a middle car B will be explained. The shock absorber  400  has a similar composition as the shock absorber  200 . A plate  150  and a support seat  215  is disposed between and on top of the left and right shock absorbers  200 ,  200  ( 400 ,  400 ), constituting the floor of the passage for the crew, etc. An anticlimber  250  is disposed on the front end of the shock absorber  400 . When a shock absorber  400  is disposed also between the left and right shock absorbers  400 ,  400 , the anticlimber  250  is mounted to the front end of this shock absorber  400 .  
         [0067]    The area above the shock absorbers  400  and the seat  215  can be the space where the entrance  510  is provided. The area can also provide space for the switch board (control panel). Moreover, it can be a space having no passenger seats. Such use of the upper area of the absorbers  400  enables minimum damage to the passengers upon collision.  
         [0068]    The end portion  500  comprising the shock absorbers  400  is removably connected to the car body  90  by bolts, similarly as the front end portion  100 . The front end of the portion  500  is not curved or protruded as portion  100 , but is perpendicular.  
         [0069]    The number of the shock absorbers  400  can be less than the number of shock absorbers disposed at the front end portion. Since the energy to be absorbed differs according to the position in the car body in which the shock absorbers are disposed, the number of shock absorbers is determined correspondingly. For example, the shock absorber  400  only has an upper layer. Moreover, the cross-sectional area of the hollow shape members  210  in the shock absorber (the area composed of the cross-sectional area of the face plates  211 ,  212  and the connecting plates  213 ,  215 ) is varied according to position. The shock absorbers equipped to the middle cars disposed near the center of the railway car comprises smaller number of members and smaller cross-sectional areas compared to the shock absorber  200  equipped at the front end  100 . The above explains the relation between the leading car and the middle car, but even when comparing the shock absorbers  500  of the middle cars, the shock absorber  500  disposed to the middle car near the center of the railway car body has smaller number of members and smaller cross-sectional area compared to the middle car  500  disposed near the end of the railway car body.  
         [0070]    There is no member for connecting the coupler  70  disposed on the end portion  500 , similar to the front end portion  100 . Upon collision, the coupler  70  drops off so that the shock absorber  400  exerts its shock absorbing function. Moreover, the end portion  500  is not equipped with a strengthening member corresponding to the hollow shape member constituting the side sill of the underframe  30 . The lower end of the plates constituting the outer sides of the end portion  500  covers the sides of the shock absorber  400 . However, the area of the end portion  500  receiving load, from the entrance  510  and the like, is equipped with members for supporting this load at the floor. This member collapses simultaneously as when the shock absorbers  400  collapse. The floor of the passenger entrance  510  and the like is supported by the shock absorbers  400 .  
         [0071]    The end portion  500  can include soft side sills. Such soft side sills can be formed by annealing or punching appropriate holes thereto. The front end portion  100  and the end portion  500  are formed separately from the car body  90  in the above embodiment, but they can also be formed integrally with the car body  90 . The hollow shape members  210  can be softened by providing holes thereto at predetermined intervals, or by selecting an appropriate plate thickness. Moreover, the construction of a common conventional shock absorber can be applied to the shock absorber of the present invention.  
         [0072]    The technical scope of the present invention is not restricted to the language used in the claims or in the summary of the present invention, but is extended to the range in which a person skilled in the art could easily substitute based on the present disclosure.  
         [0073]    The present invention enables to provide a railway car that ensures safety by absorbing the impact energy upon collision.