Hatch cover for railway cars and method of manufacturing the same

1. A hatch cover for a covered hopper railcar, said hatch cover comprising:

a substantially circular shell member having a radially outer circumferential perimeter, said substantially circular shell member comprising a topside surface and an underside surface;

a downwardly extending rim member coupled to and unitarily formed as one piece with said substantially circular shell member, said substantially circular shell member and said downwardly extending rim member define a shell/rim interface at said underside surface; and

at least one sealing gasket fixedly coupled to said underside surface proximate said shell/rim interface.

2. The hatch cover in accordance with claim 1 , wherein said substantially circular shell member and said downwardly extending rim member are substantially devoid of penetrations therethrough.

3. The hatch cover in accordance with claim 1 further comprising at least one hinge lug welded to said substantially circular shell member, wherein said at least one welded hinge lug comprises a plurality of intermittent weld beads at predetermined positions.

4. The hatch cover in accordance with claim 1 further comprising at least one latch lug welded to said substantially circular shell member, wherein said at least one welded latch lug comprises a plurality of intermittent weld beads at predetermined positions.

5. The hatch cover in accordance with claim 1 , wherein said substantially circular shell member is substantially inwardly concave and substantially ellipsoidal.

6. The hatch cover in accordance with claim 1 , wherein said hatch cover is devoid of hold down straps.

7. The hatch cover in accordance with claim 1 , wherein said hatch cover is fabricated with aluminum.

8. A covered hopper railcar comprising:

a roof assembly defining at least one substantially circular hatch port and at least partially defining at least one hopper compartment coupled in flow communication with said at least one substantially circular hatch port; and

a hatch cover configured to extend over said at least one substantially circular port, said hatch cover comprising:

a substantially circular shell member having a radially outer circumferential perimeter, said substantially circular shell member comprising a topside surface and an underside surface;

a downwardly extending rim member coupled to and unitarily formed as one piece with said substantially circular shell member, said substantially circular shell member and said downwardly extending rim member define a shell/rim interface at said underside surface; and

at least one sealing gasket fixedly coupled to said underside surface proximate said shell/rim interface.

9. The covered hopper railcar in accordance with claim 8 , wherein said substantially circular shell member and said downwardly extending rim member are substantially devoid of penetrations therethrough.

10. The covered hopper railcar in accordance with claim 8 further comprising at least one hinge lug welded to said substantially circular shell member, wherein said at least one welded hinge lug comprises a plurality of intermittent weld beads at predetermined positions.

11. The covered hopper railcar in accordance with claim 8 further comprising at least one latch lug welded to said substantially circular shell member, wherein said at least one welded latch lug comprises a plurality of intermittent weld beads at predetermined positions.

12. The covered hopper railcar in accordance with claim 8 , wherein said substantially circular shell member is substantially inwardly concave and substantially ellipsoidal.

13. The covered hopper railcar in accordance with claim 8 , wherein said hatch cover is devoid of hold down straps.

14. The covered hopper railcar in accordance with claim 8 , wherein said hatch cover is fabricated with aluminum.

15. The covered hopper railcar in accordance with claim 8 , wherein said roof assembly comprises at least one hatch wall extending substantially downward toward said at least one hopper compartment, said at least one hatch wall comprising a substantially cylindrical inner surface, wherein said at least one hatch wall defines said at least one substantially circular hatch port, said at least one substantially circular hatch port having an inner diameter of approximately 30 inches.

16. A method of assembling a covered hopper railcar, said method comprising:

manufacturing a roof assembly comprising:

at least partially defining at least one hopper compartment; and

forming at least one substantially circular hatch port coupled in flow communication with the at least one hopper compartment; and

fabricating a hatch cover configured to extend over the at least one substantially circular port, said fabricating the hatch cover comprising:

unitarily forming as one piece a substantially circular shell member and a downwardly extending rim member coupled thereto, the substantially circular shell member having a radially outer circumferential perimeter, the substantially circular shell member including a topside surface and an underside surface, the substantially circular shell member and the downwardly extending rim member defining a shell/rim interface at the underside surface; and

fixedly coupling at least one sealing gasket to the underside surface proximate the shell/rim interface.

17. The method in accordance with claim 16 further comprising welding at least one hinge lug to the substantially circular shell member comprising depositing a plurality of intermittent weld beads at predetermined positions.

18. The method in accordance with claim 16 further comprising welding at least one latch lug to the substantially circular shell member comprising depositing a plurality of intermittent weld beads at predetermined positions.

19. The method in accordance with claim 16 , wherein forming at least one substantially circular hatch port comprises forming the substantially circular shell member with a substantially inwardly concave and substantially ellipsoidal shape.

20. The method in accordance with claim 16 , wherein forming at least one substantially circular hatch port comprises fabricating at least one hatch wall extending substantially downward toward the at least one hopper compartment, the at least one hatch wall including a substantially cylindrical inner surface, wherein the at least one hatch wall defines the at least one substantially circular hatch port, the at least one substantially circular hatch port having an inner diameter of approximately 30 inches.