AU714276B2 - Steel sleeper - Google Patents

Description

ii

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT 49

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9. 4 4 9.

9994 4* 99 0 Name of Applicants: Actual Inventors: 99 99 9* 9 9 WEST JAPAN RAILWAY COMPANY YAMATO KOGYO CO., LTD.

Kenzo TOKUOKA Masafumi DEMURA Yoshihiro FUKUI Takaaki IRIE Tomokazu YANO Katsunari KONISHI Motoyoshi MARUYAMA CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, QId. 4000, Australia.

STEEL SLEEPER Address for Service: Invention Title: The following statement is a full description of this invention, including the best method of performing it known to us STEEL SLEEPER FIELD OF THE INVENTION The present invention relates to a steel sleeper and, more particularly, to a steel sleeper that is capable of preventing subsidence and buckling, and of preventing deformation due to an excessive load on the rails.

BACKGROUND OF THE INVENTION Along railway tracks, it is common to fasten rails on sleepers arranged at predetermined intervals. Recently, for the purpose of easier maintenance and reduction of operating costs, steel sleepers are increasingly being employed rather than wooden sleepers and concrete sleepers for railway tracks having few signal circuits, such as tracks in vehicle houses.

A proposed steel sleeper of this type is shown in Fig. 17, wherein a sleeper 31 (hereinafter referred to as a "conventional sleeper has a cross section that is substantially trapezoidal shape and is open at the bottom with hollow inner space.

The inner space is filled with ballast in order to prevent subsidence, and both ends of the sleeper in the longitudinal direction thereof are capped with plates. This arrangement prevents the sleeper and the ballast filling the inside thereof from being displaced in the lateral direction with respect to the track, which is termed buckling.

Fig. 18 illustrates the suspendedjoint method for supporting rails atjoints thereof by a sleeper, wherein sleepers 34 (hereinafter referred to as a "conventional sleeper are placed near to and both sides of, ajoint 33 of rails 32.

Bridge sleepers are used on bridges and are not provided with ballast. Because bridge sleepers are subjected to a greater impact and load than sleepers used to support rails on the ground, bridge sleepers generally are made of high quality timber and have large cross-sectional area. Such a bridge sleeper is illustrated in Fig. 19 wherein a wooden sleeper 35 (hereinafter referred to as a "conventional sleeper is fastened onto a bridge beam 36 by means of a hook bolt 38 with a packing 37 made of wood or a synthetic resin interposed therebetween.

Conventional sleeper 1 requires filling of the inside of sleeper 31 with ballast by pressing the ballast with a tie tamper from the side of the sleeper toward the bottom thereof. This operation is very difficult to perform, and often results in a failure to sufficiently fill the inside of the sleeper with the ballast. In cases where the sleeper is not filled sufficiently with the ballast, problems as subsidence of the sleeper, or buckling of the sleeper, can occur. The structure of conventional sleeper 1 also has a problem of being deformed when the sleeper is under a heavy load from the rails in such a way that the lower portion of the side wall is displaced outwardly and the top surface of the sleeper caves in at the center thereof, as indicated with the dash and dot line in Fig. 17. This results in the possibility of a load acting on the rail fastening that is in excess of the tolerance of the fastening, thereby causing a failure in the fastening.

In the case of conventional sleeper 2, although a widely used wooden sleeper, which provides good electrical insulation, can be used, rail-supporting capability resistance against subsidence) is inferior to the supported joint method, wherein joint 33 of rails 32 is placed at the center of a larger sleeper 39 having greater width, as shown in Fig.20. While large sleepers are made of wood, wooden sleepers are expensive. A large sleeper made of concrete is very heavy and is inconvenient to handle.

In addition to lower durability and higher cost, conventional sleeper 3 has problems as wooden sleeper 35 becomes thinner with time, thus leading to a loosened hook bolt 38, which then tends to rotate. Hook bolt 38 also eventually can drop off due to the nut being loosened by the vibration caused by running trains. Hook bolt 38 also is made longer to engage on the top surface of wooden sleeper 35, and therefore tends to bend when subjected to a horizontal force.

The present invention has been completed to solve the problems described above. Therefore, it is an aspect of the present invention to provide a steel sleeper that is capable of preventing subsidence and buckling of the sleeper, and that is less likely to change shape under an excessive load on rails. It is another aspect of the present invention to provide a steel sleeper having high rail supporting capability resistance against subsidence), having a low lost, and being relatively easy to handle. It is a further aspect of the present invention to provide a steel sleeper that is high in durability and low in cost, and that is suitable for use on bridges.

SUMMARY OF THE INVENTION In order to achieve the aspects described above, the first invention provides a steel sleeper that can be filled with ballast therein, and placed on a track bed for fastening rails thereon by means of rail fastening. The steel sleeper has a flat top flange and a flat bottom flange with a vertical web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially Ishaped configuration. Both end faces of the sleeper in the longitudinal direction thereof are capped with buckling preventing plates, and side faces of spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates are open to the outside, such that a load from the rails is transmitted via both the top flange and the bottom flange to the ballast.

The second invention provides a steel sleeper that can be filled with ballast therein and placed on a track bed for fastening rails thereon by means of rail fastening, wherein the steel sleeper has a flat top flange and a flat bottom flange with a vertical web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially I-shaped configuration. The top flange and the bottom flange are connected with buckling preventing plates at two positions, right and left, which are located at substantially equal distances in the longitudinal direction from the center of the sleeper in the longitudinal direction thereof. Side faces of spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates are open to the outside, such that a load from the rails is transmitted via both the top flange and the bottom flange to the ballast.

The third invention provides the steel sleeper of the first or the second invention, wherein the rail fastening is installed at the center of the top flange in the direction of width thereof.

The fourth invention provides a steel sleeper that can be filled with ballast therein and placed on a track bed for fastening rails thereon by means of rail fastening, wherein two steel sleepers of the same configuration are joined in parallel to each other side by side in the longitudinal direction of the sleepers.

Each of the steel sleepers has a flat top flange and a flat bottom flange with a vertical web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially I-shaped configuration. Both end faces of the sleeper in the longitudinal direction thereof are capped with buckling preventing plates. Side faces of spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates are open to the outside, such that a load from the rails is transmitted via both the top flange and the bottom flange to the ballast.

The fifth invention provides the steel sleeper of the fourth invention, wherein at least one of the top flange and the bottom flange located between the vertical web of one of the two parallel steel sleepers and the vertical web of the other steel sleeper is partially cut off at the center thereof.

The sixth invention provides a bridge steel sleeper which is placed on bridge for fastening rails thereon by means of rail fastening, wherein the bridge S leeper has a flat top flange and a flat bottom flange with a vertical web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially I-shaped configuration. The top flange and the bottom flange are connected with reinforcement plates at two positions, right and left, which are located at substantially equal distances in the longitudinal direction from the center of the sleeper in the longitudinal direction thereof. A shock absorber is interposed between the bottom surface of the bottom flange and a beam of the S bridge, or between the top surface of the top flange and the rail, or at both of these locations.

One feature of the first invention is that the cross section of the steel sleeper has substantially I-shaped configuration, while both ends of the sleeper in 0 •060 the longitudinal direction thereof are capped with the buckling preventing plates.

Side faces of the spaces surrounded by the top flange, the bottom flange, the S vertical web, and the buckling preventing plates are open to the outside such that t to9 the inside of the sleeper can be easily filled with ballast, and subsidence of the sleeper and buckling of the sleeper can be prevented. Furthermore, because the top flange and the bottom flange are in contact with the ballast, and because the load from the rails is transmitted via both the top flange and the bottom flange to the ballast, the load transfer area increases and subsidence of the sleeper can be prevented more reliably.

The cross section of the sleeper in the direction of width can include another shape added to such an extent that does not hamper the filling of the inner space with the ballast, provided that the cross section basically has a substantially I-shaped configuration.

Since the top flange is the portion where the rails are fastened thereon, it is important that the top flange has sufficient strength to bear the load from the rails. This strength can be achieved by properly selecting the material of construction, or the thickness, of the top flange.

Because the vertical web is the portion that connects the top flange and the bottom flange and transmits the load from the top flange to the bottom flange, it is important that the vertical web has sufficient strength to bear the load from the top flange. This strength can be achieved by properly selecting the material of construction, or thickness, of the vertical web.

The buckling preventing plate connects the top flange and the bottom flange, and can be a plate joined to the flanges by welding or the like.

When the top flange and the bottom flange are connected with the buckling preventing plates at two positions, right and left, which are located at substantially equal distances from the center of the sleeper in the longitudinal direction other than both end faces as in the case of the second invention, the quantity of ballast contained in the spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates is less than in the case of capping the end faces of the sleeper in the longitudinal direction by the buckling preventing plates. Therefore, the resistance of the sleeper against lateral displacement decreases, and the effect of preventing the sleeper from being displaced in the lateral direction with respect to the track, so-called buckling, decreases slightly compared to the case of capping the end faces of the sleeper in the longitudinal direction by the buckling preventing plates. However, the strength of the top flange and the bottom flange can be increased by providing the buckling preventing plates directly below the rails.

99 **The rail fastenings preferably are installed at the center of the top flange in 99• the direction of width thereof, as in the third invention. With this configuration, the load from the rails is equally distributed to the portions of the top flange and the bottom flange on both sides of the vertical web, thereby preventing the sleeper from changing shape and reliably preventing troubles from occurring in the rail fastening.

The rail fastening is not limited to a particular type. A washer type, described below in conjunction with preferred embodiment, or a wire spring clip type also can be employed. The rail fastening preferably is installed by welding because of the characteristics of the steel sleeper, in which case it is not necessary to drill a hole for a tie bolt. The possibility of cracking the steel sleeper is thereby eliminated, resulting in improved reliability.

According to the fourth invention, a steel sleeper of larger cross-sectional area having an extremely large section modulus is provided, which is less likely to change shape and has an improved rail supporting capability.

According to the fifth invention, the generation of an annoying noise, attributed to the reverberation of the noise of vehicles running on the rails, in the closed space surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates can be prevented.

While a bridge sleeper wherein an inner space is not filled with ballast is generally subjected to greater impact and greater load than in other track sections wherein the sleepers are filled with the ballast, the sixth invention provides the steel sleeper which has high durability and mitigates the impact when vehicles run thereon by means of a shock absorber interposed between the top flange and the rails, or between the bottom flange and the bridge beam.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1(a) is a side view showing one embodiment of a steel sleeper according to the present invention, and Fig. l(b) is a plan view thereof.

Fig.2 is a schematic diagram showing an end face in the right direction or the left direction of the steel sleeper of Fig. 1.

Fig.3(a) is a side view showing another embodiment of a steel sleeper according to the present invention, and Fig.3(b) is a plan view thereof.

Fig.4 is a schematic diagram showing an end face in the right direction or the left direction of the steel sleeper of Fig.3.

is a side view showing a holder piece used in the rail fastening and is a plan view thereof.

Fig.6(a) is a side view showing a washer used in the rail fastening, Fig.6(b) is a plan view thereof, and Fig.6(c) is a bottom view thereof.

Fig.7 is a front view showing the rail fastening.

Fig.8 is a plan view showing the rail fastening.

Fig.9 is a schematic diagram illustrating the action of a conventional steel sleeper.

Fig. 10 is a schematic diagram illustrating the action of the steel sleeper of the present invention.

Fig. 11 is a plan view showing another embodiment of a steel sleeper according to the present invention, and Fig. 11(b) is a schematic diagram showing an end face in the right direction or the left dirction thereof.

Fig. 12 is a plan view showing still another embodiment of a steel sleeper according to the present invention.

Fig. 13 is a side view showing still another embodiment of a steel sleeper according to the present invention.

Fig. 14(a) is a side view showing a key portion of still another embodiment of a steel sleeper according to the present invention, and Fig. 14(b) is a schematic diagram showing an end face in the left direction thereof.

Fig. 15(a) is a view showing an end face of still another embodiment of a steel sleeper according to the present invention, Fig. 15(b) is a side view of the key goo portion thereof, and Fig. 15(c) is a plan view of the key portion thereof.

go Fig. 16(a) is a view showing an end face of still another embodiment of a steel sleeper according to the present invention, Fig. 16(b) is a side view of the key portion thereof, and Fig. 16(c) is a plan view of the key portion thereof.

Fig. 17 is a sectional view showing an example of a conventional sleeper.

go Fig. 18 is a schematic diagram illustrating an example of rail supporting method with the conventional sleeper.

Fig. 19 is a sectional view showing a key portion of a conventional wooden sleeper.

is a schematic diagram illustrating another example of a rail supporting method with a conventional sleeper.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention now will be described below with reference to the accompanying drawings. In Fig.1 and Fig.2, steel S sleepers 2 are disposed on a track bed 1 at predetermined intervals in the longitudinal direction of rails. Placed on steel sleepers 2 are two rails 3, 3 fastened onto the top surface thereof by means of a rail fastening 4 separated by a predetermined distance.

Steel sleeper 2 has a top flange 5 and a bottom flange 6 with a vertical web 7 connecting top flange 5 and bottom flange 6 at the center in the direction of width thereof being formed to continue in the longitudinal direction of sleeper so that the cross section in the direction of width of sleeper 2 has a substantially Ishaped configuration. Both ends of sleeper 2 in the longitudinal direction thereof are capped with buckling preventing plates 8.

Side faces of the spaces surrounded by top flange 5, bottom flange 6, vertical web 7, and buckling preventing plates 8 are open to the outside, thereby forming a ballast packing space 9 which can be filled with the ballast. Buckling preventing plates 8 maintain the ballast in space 9 and prevent sleeper 2 from being displaced in the lateral direction with respect to the track, cooperating with the ballast.

Fastened near the center of top flange 5 in the direction of width on the top surface thereof is a pair of holder pieces 10, 10 welded at predetermined distances from a rail base 11.

Fig.3 shows a configuration similar to that of Fig. 1 except for the position of buckling preventing plate 8. Top flange 5 and bottom flange 6 are connected by buckling preventing plates 8 at the positions directly below the rails 3 (two positions, right and left, which are located at substantially equal distances in the longitudinal direction from the center of the sleeper in the longitudinal direction thereof).

Holder piece 10 has a guide portion 12, which is bent with an obtuse angle in side view, on rail 3 side of holder piece 10 as shown in Fig.5(a),and guide portion 12 is sloped with gradients in two directions of width and height of the rail.

A washer 13 is interposed between holder piece 10 and a rail base 11 as shown in Fig.l(a) and while washer 13 has a holding portion 14 formed S* substantially at right angles, as shown in side view in Fig.6(a), formed on rail base 11 side of washer 13, such that the holding portion 14 presses against the top surface and the outer edge of rail base 11. Washer 13 has a guide portion S* formed on an outer portion thereof, and guide portion 15 is sloped with gradients in two directions of width and height of the rail. Guide portion 15 of washer 13 is configured to make slide contact with the guide portion 12 of holder piece 10 such that the position thereof in the directions of width and height of the rail can be adjusted.

As shown in Fig.7, guide portion 15 is slanted from the vertical direction toward rail base 11 more than a tangent line b, at the lower end of guide portion of an arc a of which radius is a distance L between the portion where holding portion 14 of washer 13 makes contact with the outer end face of the rail base 11 and the bottom end of guide portion 15 of washer 13 on the opposite side of rail 3.

Because guide portion 15 is slanted toward rail base 11 more than the tangent line b, washer 13 can be prevented from coming off, thus making it possible to prevent rail 3 from tumbling.

As shown in Fig.7 and Fig.8, fastening of rail 3 by means of rail fastening 4 can be done by placing rail 3 between holder pieces 10, 10 on steel sleeper 2, then inserting washer 13, with the end of smaller width first, between holder piece and rail base 11, and hitting washer 13 on the wider end thereof with a hammer or the like, thereby driving washer 13. Since rail 3 can be fastened onto steel sleeper 2 without using a screw or spike, a frequency of maintenance and inspection is greatly reduced. Washer 13 can be prevented from coming off more reliably by joining guide portion 15 of washer 13 and the inner contact portion of holder piece 10 by spot welding after driving washer 13. Furthermore, because it is not necessary to drill a hole for a rail fastening bolt in steel sleeper 2, the possibility of problems, such as cracking of steel sleeper 2, can be eliminated, thus improving the durability of steel sleeper 2.

S* oIn addition, because the position of washer 13 in the directions of width and height of the rail can be adjusted by providing holder piece 10 and washer 13 with guide portions 12 and 15, respectively, and moving washer 13 in the longitudinal direction of the rail with respect to the holder piece 10, the deviation in the directions of width and height of rail base 11 due to errors in the manufacturing process can be accommodated, thereby preventing the vibration from being generated when trains run thereon.

Furthermore, because the cross section in the direction of width of steel sleeper 2 has a substantially I-shaped configuration, and because both ends of steel sleeper 2 in the longitudinal direction thereof are capped with buckling preventing plates 8, or buckling preventing plates 8 are installed at two places, right and left, which are located at substantially equal distances in the longitudinal direction from the center of steel sleeper 2 in the longitudinal direction thereof, while the side faces of the spaces surrounded by top flange 5, bottom flange 6, S* vertical web 7, and buckling preventing plates 8 are open to the outside, the •9 ballast can be packed through the open side and, accordingly, it is easier to fill the inner space of the steel sleeper with ballast. As a result, steel sleeper 2 can be prevented from subsiding. In case both end faces of steel sleeper 2 in the longitudinal direction thereof are capped with buckling preventing plates 8, in particular, the buckling of steel sleeper 2 can be surely prevented by means of the ballast which fills the inside of steel sleeper 2 and buckling preventing plates 8. The strength of top flange 5 and bottom flange 6 also can be increased by installing buckling preventing plates 8 directly below rails 3.

In the case of the conventional steel sleeper, as shown in Fig.9, the ballast on track bed 1 receives a load from a steel sleeper 16 in an area S1, which extends from the bottom surface of sleeper 16 at an angle of 450 on both ends of the bottom surface thereof downward to the outside. In the case of steel sleeper 2 of the present invention, on the other hand, because the spaces between top flange and bottom flange 6 of steel sleeper 2 are filled with ballast, as shown in Fig. the ballast on track bed 1 receives a load not only from bottom flange 6 but also from top flange 5, and therefore the load bearing area of the ballast which receives the load from steel sleeper 2 becomes greater by an area S2, thus making it possible to more reliably prevent the subsidence of steel sleeper 2.

Because holder piece 10 and washer 13 also are placed at near the center of the top surface in the direction of width of steel sleeper 2, as shown in Fig. a load transmitted from rail 3 is uniformly distributed to top flange vertical web 7 and bottom flange 6 of steel sleeper 2. Accordingly, steel sleeper 2 ~is less likely to change in shape and the troubles with fastening 4 can be S° prevented.

°Fig. 11 shows another embodiment of the present invention, wherein "o two steel sleepers of the same configuration as shown in Fig. 1 are disposed in parallel to each other side by side in the longitudinal direction of the sleeper and joined by welding. This configuration increases the section modulus, thereby making a structure that is less likely to change shape under an excessive load from the rails, that has a high resistance against subsidence, and, therefore, is suitable for the steel sleeper used under a joint of rails. In this case, a closed space 18 enclosed by the top flange, the bottom flange, the vertical web, and the buckling Spreventing plates either can be filled with ballast in advance, or alternatively not filled with ballast. Fig. 12 shows an example of such an application as the top flange located between the vertical web of one of the two parallel steel sleepers and the vertical web of the other steel sleeper is partially cut off at the center thereof, S thereby forming an opening 17. When opening 17 is formed, space 18 is no longer closed and it is possible to prevent the generation of annoying noise due to the reverberation of noise caused by trains running on the rails in the space 18 enclosed by the top flange, the bottom flange, the vertical web, and the buckling preventing plates.

Fig. 13 shows another embodiment of the present invention wherein shock absorbers 20 hard rubber) are attached between top flange 5 and rail 3, and between bottom flange 6 and a bridge beam 19, by using an adhesive, thereby mitigating the impact transmitted from rail 3 to steel sleeper 2 by means of shock absorbers 20. Numeral 21 denotes a reinforcement plate.

Fig. 14 shows an example of using shock absorbers wherein shock absorber 20 is interposed between bridge beam 19 and bottom flange 6 of steel sleeper 2 with these components being fastened by means of a hook bolt 22.

Fig. 14 is a side view of the end face. By installing the hook bolt on the bottom flange, the hook bolt can be made shorter and less likely to bend.

Fig. 15 shows another example of using shock absorbers wherein shock absorber 20 is interposed between a U-shaped bracket 23 and bottom flange 6 of steel sleeper 2, and bolts 24 are screwed through holes made in U-shaped bracket 23 to clamp shock absorber 20 to the bottom surface of bottom flange 6. Ushaped bracket 23 is welded onto bridge beam 19. This configuration makes it unnecessary to drill bolt holes in steel sleeper 2. Fig. 15(b) is a side view of a key portion of the configuration of Fig. 15(a) and Fig. 15(c) is a plan view of the key .oo: portion of the configuration of Fig. :8;"Fig. 16 shows still another example of using shock absorbers wherein shock absorber 20 is interposed between a U-shaped bracket 25 and bottom flange 6 of steel sleeper 2, while members 26 and angles 27 disposed on both sides of vertical web 7 are fastened by screwing bolts, and angle 27 and U-shaped bracket are fastened by screwing bolts, thereby pressing shock absorber 20 against the bottom surface of bottom flange 6, with U-shaped bracket 25 welded onto bridge beam 19, as shown in Fig.16(c). Fig.16(b) is a side view of a key portion of the configuration of Fig. 16(a).

As described above, the present invention has the following advantages.

S(1) According to the invention recited in claim i, ballast easily can be packed in the steel sleeper through the side openings. As a result, the subsidence of the steel sleeper can be prevented, and the displacement of the steel sleeper in the lateral e direction with respect to the track, so-called buckling, can be prevented by means of the ballast which fills the inside of the steel sleeper and the buckling preventing plates. Because the steel sleeper also has a cross section of substantially Ishaped configuration, and because the space between the top flange and the bottom flange can be filled with ballast, the load from the rails is transmitted via both the top flange and the bottom flange to the ballast, thereby increasing the load transfer area and making it possible to prevent the subsidence of the steel sleeper more reliably.

According to the invention recited in claim 3, the strength of the top flange and the bottom flange can be increased by providing the buckling preventing plates directly below the rails.

According to the invention recited in claims 2 and 4, a steel sleeper which is less likely to change in shape under an excessive load from the rails can be provided.

According to the invention recited in claim 5, a steel sleeper having an extremely large section modulus is less likely to change in shape, and has enhanced performance to resist subsidence can be provided.

According to the invention recited in claim 6, the generation of annoying noise due to the reverberation of the noise caused by vehicles running on the rails in the closed space surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates can be prevented.

According to the invention recited in claim 7, a bridge steel sleeper which mitigates the impact of running vehicles and has a high durability can be provided.

Although the present invention has been described fully by way of example with reference to the accompanying drawings, it is to be understood that various changes modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications depart from the scope of the invention, they should be construed as being included therein.

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Claims (5)

1. A steel sleeper, which can be filled with a ballast and is positioned on a track bed for fastening rails thereon by means of a rail fastening, comprising a flat top flange and a flat bottom flange, with a vertical web connecting the top flange and the bottom flange at the centers of both flanges such that an end-on cross section of the sleeper has a substantially I- shaped configuration, wherein both end faces of the sleeper in the longitudinal direction thereof are capped with a buckling preventing plate, and side faces of spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates are open to the outside, such that a load from the rails is transmitted via both the top flange and the bottom flange to the ballast.

2. The steel sleeper of claim 1 wherein the rail fastening is installed at the center of the top flange in the direction of width thereof.

3. A steel sleeper, which can be filled with a ballast and is positioned on a track bed for fastening rails thereon by means of a rail S• fastening, comprising a flat top flange and flat bottom flange, with a vertical 20 web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially I-shaped configuration, wherein the top flange and the bottom flange are connected with buckling preventing 25 plates at two positions, right and left, which are located at substantially equal distances in the longitudinal direction from the center of the sleeper in the longitudinal direction thereof, and side faces of spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates are open to the outside such that a load from the rails is transmitted via both the top flange and the bottom flange to the ballast.

4. The steel sleeper of claim 3 wherein the rail fastening is installed at the center of the top flange in the direction of width thereof. f A steel sleeper, which can be filled with a ballast and is positioned on a track bed for fastening rails thereon by means of rail fastening, comprising two steel sleepers of the same configuration are joined in parallel to each other side by side in longitudinal direction of each sleeper, wherein each steel sleeper has a flat top flange and a flat bottom flange with a vertical web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially I- shaped configuration, wherein both end faces of the sleepers in the longitudinal direction thereof are capped with a buckling preventing plate, and side faces of spaces surrounded by the top flange, the bottom flange, the vertical web, and the buckling preventing plates are open to the outside, such that a load from the rails is transmitted via both the top flange and the bottom flange to the ballast.

6. The steel sleeper of claim 5 wherein at least one of the top flange and the bottom flange located between the vertical web of one of the two parallel steel sleeper and the vertical web of the other steel sleeper is partially cut off at the center thereof. 0 7. A bridge steel sleeper, which is placed on a bridge for fastening rails thereon by means of a rail fastening comprising a flat top flange and a flat bottom flange with a vertical web connecting the top flange and the bottom flange at the centers of both flanges in the direction of width thereof being formed to continue in S* the longitudinal direction of the sleeper such that the cross section in the direction of width of the sleeper has a substantially I-shaped configuration, wherein the top flange and the bottom flange are connected with reinforcement plates at two places, right and left, which are located at substantially equal distances in the longitudinal direction from the center of the sleeper in the longitudinal direction thereof, and wherein a shock absorber is interposed either between the bottom surface of the bottom flange and a beam of the bridge, between the top surface of the top flange and the rail, or at both locations. DATED this 23rd day of December 1998 WEST JAPAN RAILWAY COMPANY and YAMATO KOGYO CO., LTD. By their Patent Attorneys CULLEN CO.