US3645213A

US3645213A - Support structure for tank car

Info

Publication number: US3645213A
Application number: US5265A
Authority: US
Inventors: William A Taylor
Original assignee: Gen Am Transport
Current assignee: General American Transportation Corp
Priority date: 1970-01-23
Filing date: 1970-01-23
Publication date: 1972-02-29
Anticipated expiration: 1989-02-28

Abstract

A support structure for a railway tank car including a fluidtight tubular body shell, first and second truck saddle structures positioned adjacent to the outer ends of the body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding the body shell and first and second elongated support structures respectively positioned between the first and second support rings and the body shell, the elongated support structures being attached along the free side edges thereof at spaced-apart points therealong to distribute stress into the body shell at a corresponding plurality of points.

Description

Taylor Feb. 29, 1972 SUPPORT STRUCTURE FOR TANK CAR Primary Examiner-Arthur L. La Point [72] Inventor: William A. Taylor, Sharpsville, Pa. Assistant Examiner Richard A Bensch [73] Assignee: General American Transportation Cory g y Clayton, Mum", Dithmar & Vogel poration, Chicago, Ill. [57] ABSTRACT [22] Filed: Jan. 23, 1970 A support structure for a railway tank car including a fluid- [21] Appl- NOJ 5,265 tight tubular body shell, first and second truck saddle structures positioned adjacent to the outer ends of the body shell [52] US. Cl ..105/362 for supponing the Same aswciated trucks each carrying [51] Int. Cl ..B6ld 5/06 draft connections first and Second external Support rings 58 Field of Search ..l05/358, 360, 362 especfively sumunding the and first and Semnd elongated support structures respectively positioned between 56] References Cited the first and second support rings and the body shell, the elongated support structures being attached along the free side MTE STATES PATENTS edges thereof at spaced-apart points therealong to distribute stress into the body shell at a corresponding plurality of points. 3,336,879 8/1967 Halcornb ..l05/358 1,154,324 9/1915 Knox ..l05/360 11 Claims, 6 Drawing Figures l/ 7 T H 7j I02 102 I56 13/ 30 I34 I23 20 P L /7/ 1 3 7/22 ngu PATENTEDF EB 29 I972 SHEET 1 [IF 3 FIG. I

INVENTOR WILL/AM A. TAYLOR PAIENTEBFEBZS 1912 3,645,213

SHEET 3 OF 3 220 225 220 225 220 225 I I I I 1 7 6 207 20 6 g 2/0 2 0l' 2 l 206 205 20 207 6 230 L Q L- w 1 l 1 l 1 l w 4' I l I 224 220 225 220 22 5 220 K225 SUPPORT STRUCTURE FOR TANK CAR The present invention relates to a support structure for a railway tank car and more specifically to an elongated support structure having attachment means spaced along the free side edges thereof to distribute stress into the body shell.

It is an important object of the present invention to provide a railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of the body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding the body shell adjacent to the outer ends thereof and secured to the body shell completely around the periphery thereof, first and second elongated support structure respectively positioned between the first and second support rings and the body shell adjacent to the outer ends thereof, the support structure extending longitudinally of the body shell, the support structure having an inboard end and an outboard end and conforming to the outer adjacent surface of the body shell, and attachment means spaced along the free side edges of the elongated support structure adjacent to the inboard ends thereof to distribute stress into the shell at a corresponding plurality of points, whereby stress due to buff and draft forces transmitted to the trucks and the associated draft connections to the elongated support structure is distributed to the body shell and the plurality of spaced-apart points.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be best understood by reference to the following specification taken in connection with the accompanying drawings in which:

FIG. 1 is a side elevational view of a part of a tank car incorporating an elongated support structure made in accordance with and embodying the principles of the present invention;

H0. 2 is a sectional view of the railway tank car shown in FIG. 1 taken along line 22;

FIG. 3 is an enlarged side elevational view of the railway tank car shown in FIG. 1, showing in further detail the elongated support structure of the present invention;

FIG. 4 is a bottom view of the railway tank car and support structure therefor shown in FIG. 3;

FIG. 5 is a sectional view of the railway tank car and the elongated support structure shown in FIG. 3 taken along line 55; and

FIG. 6 is an enlarged view of the inboard portion of the elongated support structure shown in FIG. 4;

There is illustrated and explained in detail hereinafter a railway tank car 100 including a body shell 101, first and second saddle structure at each end for supporting the same upon associated trucks 105 each carrying draft connections 120, the body shell 101 having secured therearound adjacent to the outer ends thereof first and second external support rings 150, the support structure having at the inboard ends thereof double plates 200 having attachment'means spaced along the free side edges thereof to distribute stress into the body shell 10] at a corresponding plurality of points.

As shown in the drawings, and particularly in FIG. 1 thereof, there is provided a railway tank car 100 including a tubular body shell 101 of uniform diameter closed at either end by a convex head 102 and forming a fluidtight container supported by two eight-wheel trucks 105 positioned respectively at either end adjacent to the convex heads 102, each truck 105 includes a side frame 107 carrying integral therewith a span bolster 108 extending transversely of the body shell 101, only about one-half of the car 100 being shown, it being understood that the other half is identical in structure but being the mirror image of that shown. The trucks 105 and the span bolster 108 providing support for the tank car 100 and also providing for transmission of buff, draft and rotational forces to and from the body shell 101, all as hereinafter explained. The span bolster 108 carries on the top thereof a wear ring receiver 109, the trucks 105 also including a pivot 110, the pivot 110 serving to provide the required freedom of movement between the trucks 105.

The tank car is also provided, as is usual with tank cars but not here shown, on the top thereof with a generally domeshaped manway leading to the interior of the tank car 100, the top of the tank car 100 also carrying a grating 116 extending generally longitudinally thereof. Placed around the manway and at other convenient places are a plurality of handrails 1 17, each of the handrails 117 being substantially normal to the grating 116, the handrails being made of piping each in the form of an inverted U". The manway, the grating 116 and the handrails 117 providing safe and easy access to the interior of the body shell 101, for instance to clean or to inspect the same.

There is further provided a plurality of ladder structures 118, the ladder structures 118 leading from the grating 116 to the manway and from the grating 116 to a coupling frame structure 120 carrying thereon an overgrating 121 and an upstanding frame 122, the upstanding frame 122 having connectedto the top thereof and extending outwardly therefrom a brake wheel 123. The coupling frame structure 120 also carries at the forward end thereof a standard coupler and draft gear 124 and a ladder structure 118, the coupling frame 120 and the coupler and draft gear 124 forming a draft connection for transmission of draft and buff forces to the tank car structure 100 all as hereinafter described. There is also provided in the tank car 100 a cleanout nozzles 126 at the top of the tank car and drainpipe (not shown) at the bottom of the tank car, the cleanout nozzle 126 and the drainpipe providing communication between the inside of the tank car 100 and the outside of the tank car 100 thereby to introduce and to drain a cleaning fluid therefrom, the manway providing entrance for inspection thereof.

As seen in the drawings, there is provided a slabbing structure 130, the slabbing structure 130 being cruciform in shape and having a portion 131 thereof with its greater dimension extending transversely of the body shell 101 and a portion 132 thereof with its greater dimension extending longitudinally of the body shell 101, the portions 132 having an inboard end and an outboard end, the slabbing structure 130 being suitably secured to the body shell 101 around the entire periphery of the slabbing structure 130, such as by welding, except as hereinafter explained with regard to the inboard portions of the structure 130. The outboard end of the slabbing structure 130 has an arcuate or curved end 133 and toward the inboard end of the slabbing structure 130 there is an edge 134 extending transversely across the structure 130, the entire structure 130 being rolled to conform to the outer adjacent surface of the shell 101. There is also provided a pair of longitudinally extending generally U-shaped stabilizers 135, the stabilizers having a pair of spaced-apart upstanding sidewalls 136 and a bottom wall 137 interconnecting the sidewalls 136, the sidewalls 136 being suitably secured to the slabbing portion 132 along the entire periphery of the sidewalls 136, such as by welding, the stabilizers being connected at their outer ends to the slabbing portion 132 by a pair of brackets 138 and at their inner ends the stabilizers 135 are connected to a saddle casting 140. The slabbing structure 130 and the stabilizers 135 forming with the saddle casting 140, span bolster 108, and the trucks 105 part of the support structure for the body shell 101.

At the inboard end of the slabbing structure 130, there is provided a doubler plate 200, which forms another part of the support structure for the body shell 101, it being understood as hereinbefore stated that each end of the tank car 100 rests on slabbing structure 130 and each end, therefore, has a dou bler plate 200. Each of the doubler plates 200 includes a body portion 201, the body portion 201 being rolled to conform to the outer adjacent surface of the body shell 101, the body portion 201 further including generally parallel and spaced-apart free side edges 205. The free side edges 205 of the doubler plates 200 are notched as at 206, the notches 206 being alternately spaced and each may be of the same length, the notches 206 being separated by unnotched portions 207 of the free side edges 205. As shown in the drawings, each of the free side edges 205 of the doubler plate 200 contains the same number of notches 206 therein, the notches 206 in each side edge 205 being aligned with a corresponding notch 206 on the opposite edge 205. The inboard end of the doubler plate 200 is formed into an arcuate edge 210 while the outboard end of the doubler plate 200 is formed ofa straight edge 211 extending transversely of the doubler plate 200, the transverse edge 211 being spaced apart from the transverse edge 134 of the slabbing structure 130. The doubler plate 200 is secured to the body shell 101 in a critical fashion, weldments 215 in the form of fillet welds secure the doubler plate 200 at the notches 206 to the body shell 101, but the unnotched portions 207 of the free side edges 205 are unsecured to the body shell 101, thereby to provide a plurality of relief points for the stress generated during operation of the tank car 100 to distribute, all as hereinafter explained. FIG. 5 particularly shows that the notched portion 206 of the side edges 205 are secured by the weldments 215 to the body shell 101 while the unnotched portions 207 of the free side edges 205 of the doubler plate 200 and the arcuate edge 210 are not secured to the body shell 101. There is also further a weld 216 securing the transverse edge 211 to the body shell 101, the transverse edge 211 being secured by the welds 216 along the entire length of the edge 211.

In a specific constructional example of the doubler plate 200 shown in FIG. 6, the length of the plate 200 from the transverse edge 211 to the inboardmost point of the curved or arcuate edge 210 is 4 feet, the radius of curvature of the edges 210 being 1 foot. Each of the sections 225 of the side edges 205 unsecured to the body shell is 3 inches long and each of the sections 220 secured to the body shell 101 is 9 inches long, the secured and unsecured sections being alternated as hereinbefore explained. The weldments 215 securing the sections 220 are 7/l6-inch fillet welds, and the transverse edge 211 is secured to the body shell 101 by a 58-inch weldment. The curved or arcuate inboard edge 210 of the doubler plate 200 is unsecured to the body shell 101 along 150 of arc, the edge 210 terminating at each end thereofin an unsecured section 225 of the respective free side edge 205.

It is therefore seen that the doubler plate 200 is unsecured to the body shell 101 along about 150 of arc at the inboard end 210, the doubler plate 200 is secured to the body shell 101 at spaced-apart points, as at the notches 206, along the free side edges 205 of the plate 200 and is secured to the body shell along the entire transversely extending outboard edge 211, as by weldment 216.

The saddle casting 140 carries on the bottom thereofa wear ring 141 which is received by the wear ring receiver 109, the saddle casting 140 further including, as best seen in FIGS. 3 and 4, a bottom plate 143 generally cruciform in shape and having a pair of arms 144 extending laterally of the body shell 101 and a pair of arms 145 extending longitudinally of the body shell 101, the upper edges of the laterally extending arms 144 carrying upstanding and laterally extending plates 146, the plates 146 being suitably secured to the

slabbing

131 and 132, such as by welding. As may be seen, the saddle casting 140 and span bolster 108 provide a connection between the trucks 105 and the body shell 101, and the saddle casting 140 forms a part of an external support ring 150 extending completely around the body shell 101 to support the same and transmit buff, draft and rotational forces from the span bolster 108 thereto The external support ring 150, as best seen in FIGS. 2 and 3, includes a generally U-shaped stiffening member 151, the stiffening member 151 being channel-shaped in cross section and having two parallel spaced-apart legs interconnected by a web, the legs being suitably secured to the periphery of the body shell 101 wherever the legs come in contact therewith, such as by welding, the web being relatively long and the legs being relatively short thereby to reduce the overall transverse dimension of the tank car 100. The stiffening member 151 is generally U-shaped and has an upper arcuate bight portion 155 and a lower straight portion 156, the bight or arcuate portion 155 being positioned on the top of the body shell 101 and the straight portion 156 extending downwardly from the arcuate portion 155 and being spaced from the body shell 101, the legs and web forming with the body shell 101, where the legs are welded thereto, a closed boxlike structure for a purpose to be explained hereinafter.

The external support ring 150 further includes transition plates 160 suitably secured to the stiffening member 151, the slabbing portion 131 and the body shell 101, such as by welding, the transition plates 160 having arcuate edges 162 where the plates 160 meet the slabbing portion 131 and the body shell 101. Two external bottom plates 170 and two curved jacking pads 171 are connected to the downwardly extending straight portion 156 of the stiffening member 151 and the transition plates 160; the bottom plates 170, the plates 146, the jacking pads 171, the transition plates 160 and the stiffening member 151 all being suitably secured to each other, such as by

welds

172 and 176, thereby to form with the body shell 101 a completely closed boxlike structure completely around the periphery of the body shell 101, the external support ring 150 being also operatively connected to the trucks by means of span bolster 108, the boxlike structure resulting in improved transmission and distribution of rotational forces to the body shell 101 by the support ring 150.

There is also provided a pair of side bearings 178 supported by the bolster 108 and connecting the bolster 108 with the bottom plate 143 of the saddle casting 140. The jacking pads 171 and the side bearings 178 all operate in a standard manner and fulfill the usual function.

During operation of the railway tank car 100, various buff, draft and rotational forces are created which must be absorbed or transmitted for continued safe operation of the tank car 100, the external support ring 150 providing transmission of the buff-draft and rotational forces from one of the span bolsters 108 to the body shell 101 through the body shell 101 and into the other span bolster 108 through the other support ring 150 all without the necessity of employing an underframe. The buff and draft forces are transmitted from the coupler and draft gear 124 through the coupling frame structure to the body shell 101 principally by the slabbing portion 132 and the stabilizers 135. However, the slabbing portion 131 and the stiffening member 151 also transmit some of the draft and buff forces to the body shell 101.

As seen in FIG. 2, the stiffening resistance of the support ring varies with the radial dimension thereof, whereby the upper arcuate or bight portions of the ring 150 has a relatively thin cross section and the bottom of the ring 150 has a relatively thick cross section, the horizontal midplane of the body shell 101 generally providing the dividing line between the thin cross section and the thick cross section of the support ring 150, the greatest stiffening strength of the support ring 150 being on a line at an angle of 45 to the bottom plate and passing through the center of the jacking pads 171, all tend to produce a uniform stress distribution in the ring 150, thereby saving material in the construction of the ring 150 and decreasing the cost thereof.

The external support ring 150 is secured to the body shell 101 completely around the periphery thereof to provide transmission of draft, buff and rotational forces directly between the coupler and draft gear 124, the support ring 150 and the body shell 101 without the need for continuous type underframing. The support ring 150 herein described resulting in, due to the thin and thick cross section, the closed boxlike structure and the welding to the body shell completely around the periphery thereof, not only the substantial elimination of the usual underframing, but also the elimination of any internal support structure which decreases the loading capacity, increases the weight and obstructs the internal cleaning of the tank cars, the external support ring 150 of this invention providing for the direct transmission of all forces directly to the body shell 101, whereby the buff, draft and rotational forces are transmitted from one of the coupler and draft gears 124 through the span bolster 108 through one of the support rings 150 to the body shell 101 and through the body shell 101 to the other support ring 150, through the other support ring 150 to the other span bolster 108 and to the other coupler and draft gear 124 and so on, all to provide the required distribution of forces without the usual underframing.

in tank cars without the usual continuous type of underframing, the buff and draft forces generated during operation of the tank car result in unusually high stresses introduced into the slabbing structure 130 and it is desirable to transmit these stresses to the body shell 101 along a relatively large area, thereby to maintain the stress concentration at a tolerable level. If the stress concentrations in the slabbing structure 130 become too great, the body shell 101, generally at the inboard end thereof, may buckle particularly where the body shell 101 is of a relatively small thickness. The doubler plate 200 of the present invention maintains the stress concentrations build up in the slabbing structure 130 at a tolerable level by providing interruptions in the welds 215 securing the doubler plate 200 to the body shell 101, thereby to provide a plurality of relief points for the stress to distribute from the doubler plate 200 to the body shell 101.

While there has been provided support structure for a tank car of generally uniform diameter, it is also intended to cover within the scope of this invention support structure for fishbelly tank cars and other tank cars of nonuniform diameter, of single, multiple and special truck configurations, it being understood that there has been described what is at present considered to be the preferred embodiment of the invention, but that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true scope and spirit of the invention.

What is claimed is:

1. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and secured to said body shell completely around the periphery thereof, first and second elongated slabbing structure respectively positioned between said first and second support rings and said body shell adjacent to the outer ends thereof, said slabbing structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, an elongated doubler plate coupled to and extending inwardly from the inboard edge of each said slabbing structure and conforming to the outer adjacent surface of said body shell and having notches provided in the side edges thereof, and attachment means spaced along the side edges of said elongated doubler plate in the notches thereof so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute 2. A railway tank car comprising longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and secured to said body shell completely around the periphery thereof, first and second elongated slabbing structure respectively positioned between said first and second support rings and said body shell adjacent to the outer ends thereof, said slabbing structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, an elongated doubler plate coupled to and extending inwardly from the inboard edge of each said slabbing structure and conforming to the outer adjacent surface of said body shell and having notches provided in the side edges thereof, and weldments spaced along the side edges of said elongated doubler plate so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute stress into said shell at a corresponding plurality of spaced-apart regions thereof,

whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said elongated slabbing structure and doubler plates is distributed to said body shell at said plurality of spaced-apart regions.

3. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and secured to said body shell completely around the periphery thereof, first and second elongated slabbing structure respectively positioned between said first and second support rings and said body shell adjacent to the outer ends thereof, said slabbing structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, an elongated doubler plate coupled to and extending inwardly from the inboard edge of each said slabbing structure and conforming to the outer adjacent surface of said body shell, and attachment means spaced along the side edges of said elongated doubler plate so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute stress into said shell at a corresponding plurality of spacedapart regions thereof, whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said elongated slabbing structure and doubler plates is distributed to said body shell at said plurality of spaced-apart regions.

4. The railway tank car set forth in claim 3 wherein said attachment means are evenly spaced apart along said free side edges ofsaid doubler plate.

5. The railway tank car set forth in claim 3, wherein said attachment means are weldments, said weldments being about 9 inches in length and being longitudinally spaced apart about 3 inches one from another along each of said free side edges of said doubler plates.

6. The railway tank car set forth in claim 3, wherein said doubler plates are curved at the inboard ends thereof.

7. The railway tank car set forth in claim 3, wherein said doubler plates are curved at the inboard ends thereof, each of said inboard ends of said doubler plates having a free edge for about of curvature thereof.

8. The railway tank car set forth in claim 3, wherein said doubler plates are curved at the inboard ends thereof, each of said curved inboard ends having about a 12-inch radius of curvature.

9. The railway tank car set forth in claim 3, wherein each of said doubler plates has an edge extending transversely thereof immediately adjacent the inboard end of said elongated slabbing structures, said transverse edge being secured to said body shell along the entire length of said edge.

10. The railway tank car set forth in claim 3, wherein each of said doubler plates has an edge extending transversely thereof immediately adjacent said inboard end of said elon gated slabbing structure, said transverse edge being spaced 4 feet from the inboard end ofsaid doubler plate.

11. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second support structure respectively positioned beneath said body shell adjacent to the outer ends thereof and extending longitudinally thereof, said support structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, said support structure being provided with an elongated doubler portion at the inboard end thereof, and at tachment means spaced along the side edges of said elongated doubler portion so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute stress into said shell at a correspond ing plurality of regions thereof, whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said support structure is distributed to said body shell at said plurality of spaced-apart regions.

Patent No. 3,645,213 Dated February 29, 1972 Inventor(X) William A. Taylor It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

'Claim 1, Column 5, line 53, after "tribute" insert stress into said shell at a Y corresponding plurality of spaced-apart regions thereof, whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said elongated slabbing structure and doubler plates is distributed to said body shell at said plurality of spaced-apart regions.

Signed and sealed this 27th day of June 1972.

(SEAL) Attest:

EDWARD M.F'LE'ICHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM Po-1050 (10-69) USCOMM-DC sows-P69 9 U.S. GOVERNMENT PRINTING OFFICE: 1969 O-366-334

Claims

1. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and secured to said body shell completely around the periphery thereof, first and second elongated slabbing structure respectively positioned between said first and second support rings and said body shell adjacent to the outer ends thereof, said slabbing structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, an elongated doubler plate coupled to and extending inwardly from the inboard edge of each said slabbing structure and conforming to the outer adjacent surface of said body shell and having notches provided in the side edges thereof, and attachment means spaced along the side edges of said elongated doubler plate in the notches thereof so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute

2. A railway tank car comprising longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and secured to said body shell completely around the periphery thereof, first and second elongated slabbing structure respectively positioned between said first and second support rings and said body shell adjacent to the outer ends thereof, said slabbing structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, an elongated doubler plate coupled to and extending inwardly from the inboard edge of each said slabbing structure and conforming to the outer adjacent surface of said body shell and having notches provided in the side edges thereof, and weldments spaced along the side edges of said elongated doubler plate so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute stress into said shell at a corresponding plurality of spaced-apart regions thereof, whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said elongated slabbing structure and doubler plates is distributed to said body shell at said plurality of spaced-apart regions.

3. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second external support rings respectively surrounding said body shell adjacent to the outer ends thereof and secured to said body shell completely around the periphery thereof, first and second elongated slabbing structure respectively positioned between said first and second support rings and said body shell adjacent to the outer ends thereof, said slabbing structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, an elongated doubler plate coupled to and extending inwardly from the inboard edge of each said slabbing structure and conforming to the outer adjacent surface of said body shell, and attachment means spaced along the side edges of said elongateD doubler plate so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute stress into said shell at a corresponding plurality of spaced-apart regions thereof, whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said elongated slabbing structure and doubler plates is distributed to said body shell at said plurality of spaced-apart regions.

4. The railway tank car set forth in claim 3 wherein said attachment means are evenly spaced apart along said free side edges of said doubler plate.

7. The railway tank car set forth in claim 3, wherein said doubler plates are curved at the inboard ends thereof, each of said inboard ends of said doubler plates having a free edge for about 150* of curvature thereof.

10. The railway tank car set forth in claim 3, wherein each of said doubler plates has an edge extending transversely thereof immediately adjacent said inboard end of said elongated slabbing structure, said transverse edge being spaced 4 feet from the inboard end of said doubler plate.

11. A railway tank car comprising a longitudinally extending fluidtight tubular body shell, first and second truck saddle structure respectively positioned adjacent to the outer ends of said body shell for supporting the same upon associated trucks each carrying draft connections, first and second support structure respectively positioned beneath said body shell adjacent to the outer ends thereof and extending longitudinally thereof, said support structure having an inboard end and an outboard end and conforming to the outer adjacent surface of said body shell, said support structure being provided with an elongated doubler portion at the inboard end thereof, and attachment means spaced along the side edges of said elongated doubler portion so as to provide alternating relatively long secured regions and relatively short unsecured regions therealong to distribute stress into said shell at a corresponding plurality of regions thereof, whereby stress due to buff and draft forces transmitted by the trucks and the associated draft connections to said support structure is distributed to said body shell at said plurality of spaced-apart regions.