Stub sill assemblies
Subassemblies for railroad tank cars are herein disclosed. In some embodiments, the subassembly includes a center sill including a generally horizontal top member and a pair of upright side plates spaced apart laterally from each other and a head brace having a lower margin welded to the top member of the center sill and an upper margin welded to the head of the tank. Each of the side plates having a top surface and an opposed bottom surface, the top surface being planar within a longitudinal central portion and at least a substantial part of a first longitudinal end portion. The bottom surface is planar and parallel to the top surface within the longitudinal central portion and a second longitudinal end portion. At least a substantial part of the bottom surface within the first longitudinal end portion has a shape that includes or approximates one or more radiuses of curvature.
1. A subassembly for a railroad tank car having a tank with a generally cylindrical tank body and a convex head, the subassembly comprising:
a center sill including a generally horizontal top member and a pair of upright side plates spaced apart laterally from each other; and
a head brace having a lower margin welded to the top member of the center sill and an upper margin welded to the head of the tank,
wherein each of the pair of upright side plates includes opposed first and second longitudinal end portions and a longitudinal central portion disposed between the first and second longitudinal end portions, the second longitudinal end portion being adjacent to the head brace and the first longitudinal end portion being spaced from the head brace relative to the second longitudinal end portion, each of the pair of upright side plates having a top surface and an opposed bottom surface, the top surface being co-planar within the longitudinal central portion and at least a substantial part of the first longitudinal end portion, the bottom surface being parallel to the top surface within the longitudinal central portion, the second longitudinal end portion, and a first portion of the first longitudinal end portion, and the bottom surface being co-planar within the longitudinal central portion, the second longitudinal end portion, and the first portion of the first longitudinal end portion,
wherein each of the pair of upright side plates further includes opposed first and second longitudinal end surfaces that are parallel to each other, the first longitudinal end surface is within the first longitudinal end portion, and the second longitudinal end surface is within the second longitudinal end portion,
wherein each of the pair of upright side plates further includes an inclined surface connecting the first longitudinal end surface and the bottom surface, and
wherein the entirety of the bottom surface between the inclined surface and the first portion of the bottom surface has a shape that includes or approximates one or more radiuses of curvature.
2. The subassembly of claim 1 , wherein the center sill further includes a bottom cover attached to the longitudinal central portion of the side plates and opposed to the top member, the bottom cover including a base, laterally spaced apart leg members, and spaced apart wing members, each of the leg members is attached to the bottom surface of the corresponding side plate, extends from the base toward the second longitudinal end portion, and are spaced apart laterally from each other, and each of the wing members extend from the base perpendicular to the leg members.
3. The subassembly of claim 2 , wherein the first longitudinal end portion terminates where the base of the bottom cover is attached to the bottom surface of the pair of upright side plates.
4. The subassembly of claim 1 , wherein the first longitudinal end surface has a height of not more than three inches.
5. The subassembly of claim 1 , wherein a radius of curvature of the one or more radiuses of curvature is longer than the length of the first longitudinal end portion.
6. The subassembly of claim 5 , wherein the radius of curvature is about twice the length of the first longitudinal end portion.
7. The subassembly of claim 1 , wherein a radius of curvature of the one or more radiuses of curvature is at least sixty inches.
8. The subassembly of claim 7 , wherein the radius of curvature is about ninety inches.
9. The subassembly of claim 1 , wherein the one or more radiuses of curvature includes only a single radius of curvature.
10. The subassembly of claim 9 , wherein the single radius of curvature is at least sixty inches.
11. The subassembly of claim 10 , wherein the single radius of curvature is about ninety inches.
12. The subassembly of claim 1 , wherein the at least a substantial part of the bottom surface along the first longitudinal end portion includes four or more planar segments that approximate a shape having one or more radiuses of curvature.
13. The subassembly of claim 12 , wherein the four or more planar segments includes five planar segments that approximate a shape having one or more radiuses of curvature.
14. The subassembly of claim 12 , wherein the four or more planar segments approximate a shape having only a single radius of curvature.
15. The subassembly of claim 1 , wherein the one or more radiuses of curvature includes only two radiuses of curvature.
16. The subassembly of claim 1 , wherein the at least a substantial part of the bottom surface within the first longitudinal end portion has a shape of a portion of an outer surface of an ellipse.