Articulated spine cars have been widely used in North America for carrying large shipping containers and semitrailers. The ability to transport large shipping containers by rail enables goods in the con- tainers to be transferred between container ships and railroad cars without opening the containers. Similarly, the ability to transport semitrailers by rail enables goods to be transferred between rail and highway routes without opening the semitrailers. Notwithstanding these benefits, spine cars have generally been considered unsuitable for use in Europe and in certain other regions where railways have lower weight and height limits, and where additional difficulties may be presented by bottom clearances, side clearances, and track configurations. In a typical spine car, the spine comprises a straight or linear structure, which results in the load being supported at a relatively high level. A typical semitrailer supported on a typical spine car would not comply with height limits for European railways. The elevation of the spine is typically determined by the height of the trucks which support it. Lowering a portion of the spine is problematic, due to the magnitude of the loads on the spine during use of the car.

U.S. Patent No. 5,452,664 discloses an articulated spine car for transporting semitrailers and

containers. The car comprises a pair of end units and a pair of intermediate units. Each of the units is supported by trucks at its opposite ends. Each unit comprises a central longitudinal spine which bears substantially all draft and buff loads on the car, connectors at the ends of the spine for connecting the unit to other units or cars, a wheel support platform for supporting the wheels of a semitrailer, a plurality of container supports for engaging a container, and a hitch for attachment to a semitrailer kingpin. The spine has a lowered portion adjacent the wheel support platform to provide clearance for the semitrailer axles so that the semitrailer may be supported at a relatively low level. The present invention relates to an improve¬ ment of the articulated spine cars of U.S. Patent No. 5,452,664 and U.S. patent application Nos. 08/583,500 and 08/438,463, the disclosures of which are hereby incorporated by reference herein. SUMMARY OF THE INVENTION

The invention relates to a low-level railway car for transporting semitrailers and/or containers having one or more of the features described below. The invention is preferably embodied in a lightweight, articulated spine car. The preferred articulated spine car comprises a pair of end units and at least two intermediate units. Each of the units preferably comprises a central longitudinal spine, a wheel support platform for supporting the wheels of a semitrailer, and a hitch for attachment to a semitrailer kingpin. The wheel support platforms are preferably disposed at relatively low elevations on each side of the spine, and the spine preferably includes a lowered portion between the wheel support platforms to accommodate semitrailer axles.

The spine preferably has a depressed portion for receiving a lower portion of the semitrailer hitch,

such that a hitch mount may be disposed within the depression, without projecting thereabove. This contributes to the ability to carry semitrailers at a low elevation, and, in addition, when the unit is employed for carrying containers, rather than semitrailers, the hitch may be removed, and the hitch mount will not interfere with the container.

The car preferably employs a fabricated bolster at shared bogies having a lowered intermediate portion which permits each connector pivot to be disposed at an elevation of 925 mm above rail, with each articulated connector between units of the car having a spherical bottom surface supported on a bowl which is supported on the depressed portion of the bolster and which has a spherical upper surface having a radius of curvature of 225 mm.

Each of the end units preferably has buffers mounted on substantially rectangular tubes extending transversely outward on each side of the spine which are capable of withstanding torsional stresses due to vertical loads on the buffers. The tubes are preferably backed by a pair of braces which may comprise triangular gusset plates having oblique back edges with depending flanges. The spine preferably is reinforced by a plurality of internal gussets extending transversely between the side walls of the spine and welded thereto to provide the spine with sufficient strength to support a semitrailer and sufficient strength to withstand draft and buff loads during normal operation. The spine is preferably assembled by a method wherein internal stiffeners are inserted near the ends of the spine through open ends of the spine after assembly of the top wall, bottom wall, and side walls thereof, with a first pair of stiffeners being welded in place, one near each end, by insertion of welding apparatus through the open ends, and with a second pair of stiffeners thereafter

being inserted through the open ends and welded in place.

In contrast with conventional spine car con¬ struction, the spine car of the invention preferably has a spine of nonunifor width, with the spine being narrowed adjacent the bogie wheels. This narrowing of the spine at specified locations is different from typical railway center sills or spines in which a generally uniform width is typically maintained over substantially the entire length of the spine.

Upper portions of the spine fore and aft of the semitrailer wheel support platforms are preferably configured to be sufficiently narrow to pass between a pair of I-beams which typically extend longitudinally of the bottom of a semitrailer. In prior art spine cars, the spine at these locations is typically too wide to pass between the I-beams, and is typically disposed beneath these longitudinal beams. The top wall of the spine herein preferably has a width of about 480 mm. Each of the units may be equipped with con¬ tainer support arms to facilitate transport of standard shipping containers. On each of the intermediate units, one pair of container supports is preferably disposed between the longitudinal positions of the axles of the shared bogie at one end of the unit. A second pair of container support arms on each intermediate unit prefer¬ ably has jacking pads mounted on the lower surfaces thereof, such that the second pair of container support arms also functions as jacking arms. On each end unit, a first pair of container support arms has a generally L-shaped configuration and is preferably disposed between the longitudinal positions of the end truck axles, with each arm extending transversely outward beyond the bogie wheels, and with the "L" shape enabling avoidance of interference with bogie wheels. A second pair of container support arms on each end unit is preferably disposed between the semitrailer wheel

suppσrt platforπ and the shared bogie. In the end unit, both pairs of container support arms preferably have jacking pads mounted thereon to enable the arms to serve a dual function. The bcttom wall of the spine preferably has tab extensions with holes formed therein to facilitate attachment of transverse semitrailer wheel support platform arms which extend transversely outward from the spine. The holes are preferably disposed outside of the load path along vhich draft and buff loads are transmitted through the spine. Each of the platform support arms is preferably fabricated from a tube of substantially rectangular cross section.

Further aspects of the invention are set forth in the description which follows, and shown in the accompanying dra ings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a plan view of an articulated railway car in accordance with an embodiment of the invention.

FIGURE 2 is a plan view of an intermediate unit of the articulated railway car of FIG. 1.

FIGURE 3 is a side elevational view of the unit of FIG. 2. FIGURE 4 is a longitudinal sectional view of the unit of FIG. 2.

FIGURE 5 is a plan view of the bottom cover plate of the unit of FIG. 2.

FIGURE 6 is an enlarged plan view of a portion of the wheel platform of the unit of FIG. 2.

FIGURE 7 is a sectional view taken substan¬ tially along line 7-7 in FIG. 2 and looking in the direction of the arrows.

FIGURE 8 is a bottom view of the portion of the wheel platform shown in plan in FIG. 6. FIGURE 9 is a sectional view taken substantially along line 9-9 in FIG. 7.

FIGURES 10-13 illustrate successive steps in a method of manufacturing the unit of FIG. 2, with FIG. 10 illustrating a first step; FIG. 11 illustrating a second step; FIG. 12 illustrating a third step; and FIG. 13 illustrating a fourth step in the method.

FIGURE 14 is a plan view of an end unit of the car of FIG. 1.

FIGURE 15 is a side elevational view of the unit of FIG. 14. FIGURE 16 is a plan view of the bottom cover plate of the unit of FIG. 15.

FIGURE 17 is a plan view of a connector in accordance with an embodiment of the invention.

FIGURE 17A is a side elevational view, taken partially in section, of the connector of FIG. 17.

FIGURE 17B is a sectional view taken substan¬ tially along line 17B-17B in FIG. 17.

FIGURE 18 is an end view of one of the connector members of FIG. 17. FIGURE 19 is an end view of the other connector member of FIG. 17.

FIGURE 20 is a perspective view of a portion of the wheel support platform shown in FIG. 2.

FIGURE 21 is a perspective view of an internal stiffener of the unit of FIG. 2.

FIGURE 22 is a perspective view of a portion of the end unit of FIG. 14.

FIGURE 23 is a second perspective view thereof. FIGURE 24 is a side elevational view of an intermediate unit in accordance with a second embodiment of the invention.

FIG. 25 is a partial sectional elevational view of a bolster and associated bogie and connector components in accordance with an embodiment of the invention.

FIG. 26 is a transverse sectional elevational view taken substantially along line 26-26 of FIG. 24. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS General Arrangement The invention is preferably embodied in an articulated railway car which comprises a plurality of car units joined to one another by connectors. FIG. 1 illustrates an articulated railway car 10 comprising four units 12a, 12b, 12c, and 12d joined by connectors 14. Each unit generally comprises a longitudinal spine 16 as its main load-bearing member, and is preferably adapted for carrying either containers or semitrailers. In other embodiments, the car may be adapted for carrying only semitrailers, or only containers. Each of the end units 12a and 12d has a suitable coupling for connection to an adjacent car, and has a pair of buffers at its outer end for transmitting buff loads to and from adjacent cars. The intermediate units 12b and 12c are joined to each other and to the end units by the pivotal connectors 14.

Each unit has a wheel platform 18 for support¬ ing the wheels of a semitrailer, and a hitch 20 for engaging the semitrailer kingpin. Each unit preferably also includes four container supports 22 for engaging the corners of a shipping container.

Each of the end units 12a and 12d includes an end truck or bogie at its outer end, and has its inner end supported by a shared truck or bogie. The inter¬ mediate units have their inner ends supported by a center shared truck, and have their outer ends supported on trucks shared with the end units.

On each unit, the container supports 22 are positioned such that the container supported thereon will not be centered between the trucks associated with that unit, but rather will be closer to the outer truck than the inner truck. Thus, assuming that the container is uniformly loaded, i.e., that the weight of the

container is distributed evenly along its length, more than one-half of each container's weight will be carried by the outer truck of the unit on which the container is supported. This distributes the loads on the respective trucks more evenly than would centering the containers between the trucks, because if the load were positioned centrally between the trucks of each unit, the end trucks would be more lightly loaded than the shared trucks. To facilitate acceptable load distribution without unduly increasing the length of the car, each of the end units 12a and 12d is longer than each of the intermediate units 12b and 12c, and in each of the end units, the wheel support platforms 18 are located at a greater distance from the inner end of the unit than in the intermediate units.

On each unit, each of the wheel support platforms 18 preferably is only as long as necessary to support the rear wheels of a semitrailer having the longest conventional dimensions for its set of rear wheels. Thus, as shown in FIG. 24, the wheel platform is preferably slightly shorter than the rear wheel set of the illustrated semitrailer 124. As described in greater detail below, each of the preferred units 12a through 12c preferably has a recess in its spine to accommodate the axles of a semitrailer, with the deepest part of the recess being slightly shorter than the length of the wheel platform, and with the recess being only as long as necessary to accommodate the axles of the rear wheels of a conventional semitrailer having the maximum conventional length for its rear wheel set.

Intermediate Units An intermediate unit 12b is shown in detail in FIGS. 2-5. Each intermediate unit 12b comprises a central spine 16 having a first connector member 24 at one end and a second connector member 26 at the opposite end for joining the unit to an adjacent unit. Each of

the connector members 24 and 26 preferably comprises a casting. At the outer end 28 of the unit, a first pair of arms 30 mounted on the first connector member 24 supports both a pair of upper side bearings 32 and a pair of container supports 22. At the inner end 34, a second pair of arms 36 mounted on the second connector member 26 supports a second pair of upper side bearings 37. The wheel support platforms 18 are positioned near the inner end also. The connectors and associated arms of two adjacent units are shown in greater detail in FIGS. 17-19, in connected position.

A dip or lowered portion 38 is provided in the spine between the wheel support platforms 18 to provide clearance for semitrailer axles. Each of the wheel support platforms 18 is supported by a plurality of transverse arms 40 which extend outward from the lowered portion 38 of the spine and extend beneath the wheel support platforms 18.

Between the wheel support platforms 18 and the inner end 34 of the unit 12b, a second pair of container supports 22 are provided on a pair of L-shaped container support arms 42. Each of the L-shaped container support arms 42 includes a transverse portion 44, extends transversely outward from the spine 16 near its upper surface, and has a longitudinal portion 46 extending from the end of the transverse portion longitudinally toward the end of the car. Jacking pads 48 are preferably affixed to the lower surfaces of the arms 42 at the corner where the transverse portion joins the longitudinal portion.

A second pair of jacking pads 50 is provided on a pair of jacking pad arms 52 located adjacent the semitrailer hitch.

The spine 16 is of substantially rectangular cross section, comprising a pair of side walls or webs

54, a bottom wall 56 or bottom cover plate 56, and a top wall or top cover plate 58. The bottom and top walls

extend laterally beyond the side walls of the spine to provide upper and lower flanges 60 and 62 along both sides of the spine.

The bottom flanges 62 provide support for the platform support arms 40. The bottom wall 56 has a plurality of tab extensions 64 to provide additional support and facilitate attachment of the platform support arms. Each of the tab extensions has a hole 66 therein to facilitate welding of a platform support arm to the spine.

Each of the platform support arms is prefer¬ ably a square tube having a top wall, a pair of side walls, and a bottom wall. The inner end of each of the arms preferably abuts a side wall of the spine and is preferably welded to the side wall of the spine along its top and sides. The bottom of each arm preferably contacts the lower flange 62 of the spine and is welded thereto about the periphery of the hole 66 in its associated tab extension 64. To prevent the attachment of the platform support arms from weakening the spine, the holes 66 are preferably outside of the load path through the bottom wall along which draft and buff loads are transmitted, and to this end are preferably disposed outward of the adjacent outer edge portions 68 (FIG. 8) of the bottom wall 56.

As shown in FIGS. 7 and 20, each of the plat¬ form support arms 40 has an upper end portion cut away to enable it to receive one of the wheel platforms 18. A portion of the top wall of the support arm 40 is cut away, and an upper portion of each of the side walls of the support arm 40 is also cut away. Only lower portions of the side walls and the entire bottom wall extend the full length of the support arm. The upper portions of the side walls of the support arm 40 are cut away at an angle to provide a downward slope corresponding to that of the inner wall of the wheel support platform as described below.

As shown in FIG. 7, each of the wheel plat¬ forms generally comprises a bottom wall 70, an inner wall 72 which slopes upward and inward from the bottom wall, and an outer wall 74 which slopes outward and upward from the bottom wall. Each platform extends longitudinally to receive up to three semitrailer tires. The downwardly-convergent inner and outer side walls 72 and 74 are spaced from each other by a sufficient distance to accommodate the full width of a tire, but the outer walls are positioned so as to urge the outer side walls of the tires inward somewhat to securely hold the semitrailer wheels against side-to-side movement.

At the outer end of each of the platform support arms 40, a lateral plate 76 extends outward to engage the bottom of the platform 18, and also extends inward and upward between the exterior of the inside wall 72 of the platform and the cutaway end portion of the arm 40. The lateral plate 76 preferably extends beyond the end of the support arm to provide additional support for the platform.

Each of the platform support arms 40 extends beneath only an inner portion of the bottom of the platform, tc provide increased clearance beneath the outer porticr: of the platform. To provide additional support for the platform, the lateral plates 76, which are of relatively small vertical dimension, extend beyond the ends of the arms in the illustrated embodiment. Each of the lateral plates has a vertical dimension less than that of the portion of the arm that extends beneech the platform for increased clearance. In the illustrated embodiment, the lateral plates 76 extand beneath the intermediate portion of the platform and are of solid cross section. The bottom of the platform _.s partially self-supporting in that the lateral plates, terminate inward of the outer portion of the bottom of the platform.

To provide for low-level support of the semitrailer, each of the platforms 18 in the illustrated embodiment is disposed below the lowered intermediate portion 96 of the top wall of the spine. Furthermore, the bottom 70 of each platform is disposed below the upper surfaces of the support arms 40. Each of the arms 40 is, in the illustrated embodiment, of a generally rectangular, hollow cross section, comprising a top wall 214, a bottom wall 216, and substantially parallel, substantially vertical side walls 218. The bottom wall 216 extends outward beyond the top wall 214, and each of the side walls is cut away so that a lower portion 220 of each side wall extends beneath its associated platform. The illustrated wheel support arrangement thus provides a strong, rigid, low-level structure for supporting the semitrailer wheels, while also providing adequate clearances at the bottom and sides of the car to comply with clearances on European railways. At the ends of the unit, the bottom wall 56 of the spine is at a relatively high elevation to clear wheel axles and other truck components. However, lower portions of the spine extend at an elevation below the tops of the wheels as it passes between them. Proceeding inward from the ends, the bottom wall 56 slopes downward to a generally horizontal intermediate portion 78. The intermediate portion 78 of the bottom wall extending beneath all four of the platform support arms is of increased thickness. The top wall 58 has a generally similar configuration in that it has end portions disposed at a relatively high elevation, and a depressed or lowered intermediate portion 96 along which the side walls have a correspondingly reduced vertical dimension to define the dip depression 38 in the spine. However, the dip 38 preferably is only as long as necessary to provide clearance for semitrailer axles between the wheel

platforms. Thus, the spine 16 has a relatively large vertical dimension and a relatively large moment of inertia over a substantial portion of its length between the wheel platforms and the semitrailer hitch. This contributes to the stiffness and strength of the spine. To further contribute to the strength and stiffness of the spine, a plurality of gussets or stiffeners are provided on the interior of the spine. On the interior of the spine adjacent the platform support arms, transverse stiffeners 82 having a cross section generally similar to that of the platform support arms extend transversely between the side walls, and one or more additional transverse vertical stiffener plates 84 extend upward therefrom to the top wall of the spine. Each of the transverse stiffeners 82 preferably includes an inverted U-shaped or channel-shaped member 86 welded to a bottom stiffener plate 88. Gussets 83 are also provided at the locations of the jacking/container support arms. As described in greater detail below, at each location along the spine 16 where the bottom wall 56 or the top wall 58 is curved or bent, one or more gussets are preferably provided, welded to the inside of the curved portion of the top or bottom wall, and welded to the side walls 54 as well at that location.

Longitudinal stiffeners or "third webs" 90 are provided centrally of the bottom wall 56 at the ends of the lower intermediate portion 78 thereof. Each of these longitudinal stiffeners intersects transverse stiffeners or gussets 91. Each of the transverse stiffeners or gussets 91 preferably comprises two pieces, one on each side of the third web 90, extending from the third web to a side wall.

The top wall 58 has an intermediate portion 92 of increased thickness, extending between a location forward of the wheel platforms 18 and a location between the L-shaped container support arms 42 and the inner end

34 of the unit. Each side wall has a pair of generally crescent-shaped web doublers 94 welded to its exterior surface adjacent the ends of the generally horizontal lower intermediate portion 96 of the top wall of the spine.

Upper portions 98 and 100 of the spine fore and aft of the depression 38 are sufficiently narrow to pass between a pair of I-beams or other structural members which typically extend along the bottom of a semitrailer. Thus, in contrast with typical spine cars wherein a relatively wide spine is employed, these upper portions of the spine preferably have a width of about 480 mm or less.

FIG. 24 illustrates an intermediate unit 102 in accordance with a second embodiment of the invention which is substantially similar to that described above with reference to FIGS. 1-9, except that in the embodi¬ ment of FIG. 24, the top of the spine 110 includes lowered portions 106 and 108 near the ends of the spine. This configuration enables the top wall 104 of the spine at the ends of the spine to be substantially aligned with the top of the connector top wall, while enabling adjacent portions of the spine disposed inward of the ends to have a greater vertical dimension for increased strength by virtue of increased elevation of the top wall 104 inward of the end portions. In addition, at the outer end of the unit, this provides a recess for a hitch mount.

FIG. 24 also illustrates, in broken lines, the position of a semitrailer 124 and a container 126, either of which may be supported on the unit in the position illustrated thereon. As in the first embodiment described above, upper portions 112 and 114 of the spine fore and aft of the depression 116 in the unit of FIG. 24 are sufficiently narrow to pass between a pair of I-beams 122 which extend along the bottom of a semitrailer (see FIG. 26) . As shown in FIG. 26, the

bottom wall 118 is preferably wider than the top wall 104, and the side walls 120 preferably are substantially vertical. The top wall 104 preferably- has a width of 480 mm fore and aft of the depression 116. Assembly of Spine

In a preferred method of assembling the spine, assembly of the spine and welding of various components of the spine are facilitated by employment of a sequence of assembly steps which enable welders to obtain access to interior welding locations that are inaccessible after assembly of the spine has been completed, and which also enable manufacturing specifications and tolerances to be maintained in an efficient manner.

In the method of assembling the spine for the intermediate units shown in FIGS. 10-13, each side wall or web 54 is formed from three separate web sections 128, 130, and 132 which are welded together along vertical web splices. After assembly of the side walls, upper transverse stiffeners 134 and 136 are welded between the side walls at locations corresponding to curves or bends in the top wall. The upper stiffeners 134 and 136 are angled so as to extend generally perpendicular to the top wall at the locations where they are welded to the top wall. The transverse stiffeners 82 which will align with the platform support arms and a first pair of transverse end stiffeners 146 are also welded in place between the two side walls, as are the stiffeners 83 at the jacking/container arm positions. The partially assembled spine at this point is shown in FIG. 10.

Thereafter, the top cover plate 58 is welded to the side walls as shown in FIG. 10, and the trans¬ verse stiffeners 82, 134, and 136 are welded to the top cover plate 58. The top cover plate comprises a forward section 150, a central section 152 of increased thickness, and a rear section 154. The central section

152 has greater thickness than the end sections 150 and 154.

The longitudinal stiffeners or third webs 90 and their associated transverse gussets 91 are welded to a bottom cover plate 56 at the lower radius points, and the bottom cover plate 56 comprising t.'ιree separate cover plate sections 140, 142, and 144, is then tack welded to the side walls (see FIG. 12) .

The first pair of transverse end stiffeners are then welded to the bottom cover plate at each upper radius of the bottom cover plate, with access for welding being obtained through the ends of the spine. A second pair of transverse end stiffeners 148 are then inserted through the open ends and welded to the bottom wall and side walls at each upper radius of the bottom wall. Each of the second pair of stiffeners 148 is located closer to the open end of the spine than the adjacent, previously-installed first stiffener.

Thereafter, the welding of the side walls to the top and bottom cover plates is completed, and connectors 24 and 26, a semitrailer hitch 20, and web doublers 94 are installed (see FIG. 13) along with platform support arms and other assemblies.

All of the gussets or stiffeners attaching to the main spine top cover plate and side walls are welded on three edges using either double-sided fillet welds or penetration welds welded from one side. Where penetra¬ tion welds are employed, the edges of the gussets are chamfered on the sides to be welded so that beads of welding may be placed in the resulting grooves between the gusset and the surface to which it is being welded. The gussets and third web attached to the main spine bottom cover plate at the lower radius points are attached to the bottom cover plate only. Double-sided fillet welds or penetration welds welded from one side are used at this location.

The gussets 146 and 148 in the upper radius area are welded to both the bottom cover plate and the side walls. Full penetration welds are preferably used to attach the main spine web doublers to the top cover plate.

A similar method of assembly is employed for the end units. However, in assembling the end units, a main cover plate splice may be necessary in the bolster area over the end bogie to allow attachment of the gussets in that area, because the end unit will not have an end opening for an articulated connector in this area.

Alternative Method of Assembly As an alternative to the sequence of assembly steps described above, the spine may be assembled in three separate sections, as described below.

In the alternative method, the center section side walls 130 are first welded to the internal stiff¬ eners 82 and 134 in that section. The center section top cover plate is then tacked to the side walls, and the stiffeners 82 and 134 are then fully welded to the top cover plates. One additional stiffener 136 may also be welded to the top cover plate at this time.

The end portions 128 and 132 of the side walls are then welded to their associated gussets, after which the bottom cover plates 140, 142, and 144 are tacked in place, and the gussets are then fully welded to the bottom cover plates. At this point, the center section is joined to the end sections. The center bottom cover plate 142 is then tacked to the side walls, and the top cover plates of the end sections 150 and 154 are also tacked in place. The end sections 150 and 154 of the top cover plate are then completely welded to the middle section 152 thereof, and the end sections 140 and 144 of the bottom cover plate are completely welded to the middle section 142 of the bottom cover plate. Thereafter, longitudinal fillet welds are completed

between the side walls and the respective top and bottom cover plates.

The articulated connectors, hitch, and web doublers are then welded in place, after which the side bearing arms, container support arms, wheel platforms, and jacking pad arms are welded in place.

End Units An end unit 12a is illustrated in FIGS. 14-16 and FIGS. 22 and 23. The end units are generally similar to the intermediate units, except as discussed herein.

Each end unit comprises a central spine 155 having a connector member 26 at one end for joining the unit to an adjacent unit of the articulated car. At the opposite end, the end unit has a coupling or hook 156 for connecting the end unit to an adjacent railway car, and has a pair of buffers 158 for transmitting buff loads between the end unit 12a and the adjacent car. The coupling and buffers are, of course, located at the outer end of the end unit, i.e., at the end which functions as the end of the car, whereas the connector is located at the inner end, i.e., the end nearer the center of the articulated car.

At the inner end, a pair of side bearing arms 160 are supported on the connector member 26, and a pair of upper side bearings 162 are mounted on the arms for cooperation with lower side bearings mounted on the shared truck.

Also at the inner end, a pair of wheel support platforms 18 are provided. Each of the wheel support platforms is supported on a plurality of transverse arms 40 extending outward from a lower portion of the central spine. A dip or recess 164 is provided in the spine between the wheel support platforms 18 to provide clearance for semitrailer axles.

Near the outer end of the unit, a semitrailer hitch 20 is provided so that a semitrailer may be

supported with its front end adjacent the outer end of the car, and a pair of generally L-shaped container support arms 166 are also provided near the outer end. Each arm extends transversely outward, perpendicular to the spine, between the twin axles of the end truck.

Each of the arms 166 has a transverse portion extending outward from the spine, and a short longitudinal portion extending generally perpendicular thereto, longitudi¬ nally toward the end of the car. Each of the container supports 22 is located near the end of the longitudinal portion of the arm, with the "L" shape avoiding inter¬ ference between the arm and the wheels 168 and 170 on the outer axle of the end bogie.

A second pair of container support arms 172 is provided near the inner end of the car, between the wheel platforms 18 and the inner end of the car.

The container supports 22 are positioned asymmetrically relative to the bogies such that, assuming that the container load is uniformly distri- buted over the length of the container, the container load will not be evenly distributed between the bogies, but rather a greater portion of the container load will be borne by the end bogie than by the shared bogie at the inner end of the end unit. Each of the four container support arms has a jacking pad 174 affixed to a lower portion thereof.

The spine is not of uniform cross section, but is of substantially rectangular cross section over sub¬ stantially all of its length. The spine comprises a pair of side walls or webs 176, a bottom wall 178, or bottom cover plate, and a top wall or top cover plate 180.

The bottom wall 178 is not of uniform width, but rather has a widened portion 182 at the location of the recess 164 at which the platform support arms 40 are affixed to the spine, and has narrowed portions 184

adjacent each of the axles to provide clearance from disc brake components at these locations.

To enable containers to be carried on the unit without interference between the container and the semitrailer hitch, the semitrailer hitch 20 is preferably movable or removable. To facilitate low- level support of semitrailers and containers, the hitch is preferably mounted in a recess 186 in the top of the spine, as best seen in FIG. 15. Upstanding mounting lugs 188 (FIGS. 23 and 24) are provided in the recess for removably securing a semitrailer hitch in place. The lugs preferably do not project above adjacent portions of the top wall of the spine. The recess is defined by gradually sloping portions 190 of the top wall disposed fore and aft of the recess. The slope of these portions is very gradual so as to avoid unduly high stress concentrations near the recess in response to draft and buff loads, coupled with the loads supported by the semitrailer hitch. Substantially vertical gussets 192 are preferably welded to the top wall and side walls at each end of the sloping portions 190 to further strengthen the spine in this area.

Bogies Each of the connectors 14 has a convex spher- ical bottom surface which is received in a complementary concave spherical top surface of a bowl 194 (FIG. 25) which is supported on a shared bogie. The respective spherical surfaces preferably each have a radius of about 225 mm. While it is generally desirable to employ standard, proven bogie configurations at the articu¬ lation of the car, it has been found that use of the above-described spherical surfaces with existing bogie configurations would result in a need to position the connectors at an unacceptably high elevation.

In accordance with the preferred embodiment of the invention, each shared bogie comprises conventional

side frames and wheels, but has a bolster 196 extending between the side frames which has a top surface 198 which slopes downward from the ends 20.0 of the bolster to the truck-mounted bowl so that the truck-mounted bowl may be supported at a relatively low elevation. This enables the center of rotation of the pivotal connection between the connector members and the bowl to be main¬ tained at a standard height of 925 mm above the rail, while also maintaining the spherical bowl radius of 225 mm.

The illustrated bolster comprises a top wall 202, a bottom wall 204, and at least one substantially vertical web 206 joining the top and bottom walls. Reinforcing longitudinal stiffeners 208 extend downward and outward from beneath the truck-mounted bowl, from the top wall 202 to the bottom wall 204.

The bolsters 196 are preferably fabricated, although a cast bolster may alternatively be employed in other embodiments of the invention. A similar bolster is used on the end bogies.

Connectors The first connector 24 preferably comprises a single, unitary steel casting having an end portion 232 which has an end opening 234 for receiving an end portion 236 of the second connector member 26. In the illustrated embodiment, the end portion 232 of the first connector 24 comprises a top wall 240 and a bottom wall 242 having aligned circular openings formed therein for receiving a vertical pivot pin 238 and fitting closely therewith. The end portion 236 of the second connector member 26 also has a vertical opening formed therethrough for receiving the pin 238.

The second connector member 26, like the first connector member, preferably comprises a one-piece, unitary integral casting. The first and second connector members preferably are joined by the vertical pivot pin 238 which extends through the openings in the

respective connector members. The pivot pin is rigidly connected to the first connector member.

The first and second connector members 24 and 26 are preferably free to pivot relative to one another about any axis, i.e., about transverse and longitudinal horizontal axes, as well as about the vertical axis of the pivot pin 238. To provide for transmission of draft and buff loads between the first and second connector members without uncontrolled slack while also permitting them to pivot relative to one another about any axis, a generally cylindrical elastomeric bushing 244 is provided between the pivot pin 238 and the second connector member 26 so that the second connector member is not rigidly constrained by the pin. The elastomeric bushing is disposed between an inner metallic ring or sleeve 246 which contacts the pin, and an outer metallic ring or sleeve 248 which contacts a generally cylin¬ drical interior surface of the end portion 236 of the second connector member. The bottom wall 242 of the end portion 232 of the first connector member 24 has its upper surface 250 formed with a spherical concave configuration for engagement with a complementary spherical bottom surface on a wear ring 252. The wear ring 252 has a spherical upper surface which engages a spherical bottom surface of another ring 254, which has a horizontal upper surface engaging the second connector member to transmit vertical loads between the first connector member 24 and the second connector member 26. In accordance with a feature of the illus¬ trated embodiment, the bottom surface 256 of the bottom wall 242 is convex and spherical, i.e., shaped as a portion of a sphere, and is supported on a complementary concave upper spherical surface of the bowl 194. A wear ring 260 is disposed between the bottom of the first connector member and the upper surface of the bowl. The spherical surfaces of the bowl 194, bottom wall 242, and

rings 252, 254, and 260 described above preferably share the same center of curvature, which is preferably disposed at the vertical midpoint of the elastomeric bushing at an elevation of 925 mm above the rails. The pivot pin 238 preferably has an enlarged head 262 which acts as a stop to limit downward vertical travel of the pin, and preferably has a bolt 264 extend¬ ing from its lower end through an opening in the bowl 194 with a nut 266 thereon engaging a washer 268 which bears against the bottom of the truck-mounted bowl to prevent or limit upward vertical displacement of the pin and to hold the pin 238 rigidly and fixedly in place relative to the first connector member 24. This arrangement also prevents the connector members from being lifted from the bowl 194. The bowl 194 preferably has an opening which is sized much larger than the bolt 264 to permit the first connector member 24 to pivot on the bowl 194.

The washer 268 and the bottom surface of the bowl 194 engaged by the washer preferably have comple¬ mentary spherical configurations, i.e., each is shaped as a portion of a sphere, centered about the same center of curvature as the other above-described spherical surfaces, so that the washer may be fixed relative to the bolt, and may move slidably relative to the truck- mounted bowl, so that the first connector member 24 may pivot about any axis relative to the truck-mounted bowl while remaining firmly connected to the bowl 194.

The elastomeric bushing 244 enables draft and buff loads to be transmitted between the connector members without uncontrolled slack, while permitting pivoting of the members relative to one another as described above.

The first connector member has a pair of stub arms 270 formed thereon, extending generally upward and outward from a central longitudinal portion of the casting, to support the arms 30 on which upper side

bearings 32 and container support 22 are mounted. Similarly, the second connector member 26 has a pair of stub arms 272 extending generally upward and outward therefrom to support the arms 36 which support the upper side bearings 37.

The truck-mounted bowl 194 is relatively shallow to enable draft and buff loads to be transmitted at a relatively low level while providing an adequate range of motion for the connector members relative to each other and to the truck-mounted bowl. To this end, the bowl is configured such that a line drawn from a point on the upper edge of the upper surface of the truck-mounted bowl to its center of curvature intersects a vertical line at an angle α (FIG. 17A) of about 55°. The upper surface of the truck-mounted bowl preferably has a radius of curvature less than 400 mm, and in the illustrated embodiments has a radius of curvature less than 300 mm. In one embodiment, the radius of curvature is 225 mm. In a second embodiment, the radius of curvature is 275 mm.

Selection of an appropriate radius of curvature is important from the standpoint of enabling the desired geometry to be achieved, to permit the desired range of pivoting of the connector members relative to each other and the truck-mounted bowl, while also providing adequate strength for the connector members, and enabling draft and buff loads to be trans¬ mitted through the connector at a relatively low level. The connector is preferably intended to be capable of bearing vertical loads on the shared truck of about 39.6 metric tons, or about 87,300 lbs.; 2,000 KN (450,000 lbs.) buff; and 1,500 KN (337,000 lbs.) draft. In the illustrated embodiment, as best shown in FIG. 17A, draft and buff loads are transmitted at a level below the elevated end portions of the spine. That is, draft and buff loads are transmitted between the first connector member 24 and the second connector member 26 through the

elastomeric bushing 244 with the center of effort of such loads being disposed approximately at the center of curvature of the truck-mounted bowl. This geometry contributes to the ability of the subject railway car to support semitrailers and containers at a relatively low level.

Each of the connector members 24 and 26 preferably consist essentially of a one-piece, integral casting. The stub arms 270 and 272 on the connector castings 24 and 26 extend upward and outward from central portions of their respective castings, leaving a region at the center of each connector member between the arms which is below the level of the upper surfaces of the arms. In the illustrated embodiment, a channel member 274 is provided between the stub arms 270 on the first connector member 24 to increase the strength and stiffness thereof. The channel member 274, as shown in FIGS. 17, 17B, and 19, has its ends curved to fit between the stub arms, and is welded in place there- between. In other embodiments of the invention, it may be desired to provide a trailer hitch at this location. To eliminate the need for the channel member, heavier walls may be provided in the connector casting. End Unit Buffer Support Structure To transmit buff loads through the buffers 158 to the spine 155, while also adequately supporting the buffers 158 to resist vertical forces thereon, a tube 208 of generally rectangular cross section extends transversely outward on each side of the spine 155 at the outer end of each end unit, and on each side of the spine, the rectangular tube is backed by a brace or gusset 210. The rectangular tube is capable of with¬ standing torsional loads due to vertical loads on the buffers. Each brace or gusset 210 in the illustrated embodiment is a triangular plate which is welded to the top of the tube 208 and welded to the spine 155. Each of the triangular plates 210 has a depending flange 212

extending at an angle of about 45° to the tube and to the spine, along its back edge, i.e., the edge extending from its outer corner to the spine, to increase stiffness. The tube 208 and braces 210 are preferably employed without any other buffer-supporting frame. Thus, in contrast with more typical arrangements in which buff loads are transmitted at least in part to longitudinal members of a frame disposed behind the buffers, the buff loads are transmitted directly to the spine near the outer end of the car, eliminating the need for a large frame with side sills at the end of the car. The braces 210 preferably extend rearward only to a location nearer the end of the unit than the center of the outer axle of the end bogie. From the foregoing, it should be appreciated that the invention provides a novel and improved railway car. The invention is not limited to the embodiments described above, nor to any particular embodiments, but rather is defined by the claims as set forth below. In the following claims, the term "spine car unit" is used broadly to denote not only units of an articulated car wherein adjacent units are connected at shared trucks, but also to denote stand-alone nonarticulated cars.