Railroad car and floor structure therefor

Abstract

A railroad box car has a combined underframe and floor structure that includes a floor sheet having an upper surface upon which to carry lading, and an underside to which a center sill, cross-members, and floor stringers are welded. The floor sheet defines the upper flange of the center sill, the cross-members, and the stringers, such that the center sill, cross-members, and stringers are mutually flush. For assembly, the floor sheet is upside-down, and the center sill webs, stringers, and tie-down mounting rails to it with longitudinal welds. The cross-members and center sill web separators are positioned cross-wise and welded in place. The floor sheet is a non-nailable surface that caps the underframe structure. The stringers are channels welded toes-in to the underside of the floor sheet with the spacing between the center sill web, stringer toes, and edge channel rails being roughly equal.

We claim: 
     
         1 . A box car floor assembly comprising:
 a floor sheet having a length and a width; an array of cross-members; and a set of stringers;   said set of stringers being oriented to run lengthwise relative to said floor sheet;   said set of cross-members being oriented to run cross-wise relative to said floor sheet;   the floor sheet having an upper surface that defines the lading surface of the floor assembly; and   the cross-members having accommodations formed therein through which the stringers pass uninterrupted.   
     
     
         2 . The box car floor assembly of  claim 1  wherein said floor sheet defines the upper flange of said array of cross-members. 
     
     
         3 . The box car floor assembly of  claim 1  wherein said floor sheet defines the upper flange of the stringers of said set of stringers. 
     
     
         4 . The box car floor assembly of  claim 1  wherein said floor sheet defines the upper flange of said array of cross-members; and said floor sheet defines the upper flange of the stringers of said set of stringers. 
     
     
         5 . The box car floor assembly of  claim 1  wherein said box car floor assembly includes a straight-through center sill and said floor sheet defines a center sill cover plate of said center sill. 
     
     
         6 . The box car floor assembly of  claim 5  wherein said floor sheet defines the upper flange of said array of cross-members; and said floor sheet defines the upper flange of the stringers of said set of stringers. 
     
     
         7 . The box car floor assembly of  claim 1  wherein said floor sheet is a non-nailable floor sheet. 
     
     
         8 . The box car floor assembly of  claim 1  wherein:
 said floor assembly has laterally outboard margins and has tie-down fittings mounted along said laterally outboard margins; 
 said floor assembly has reinforcement rails mounted along said laterally outboard margins to which said tie down fittings are mounted; and 
 said cross-members have webs that are located underneath said floor sheet and said cross-member webs have notches formed therein, said reinforcement rails being mounted in said notches. 
 
     
     
         9 . The box car floor assembly of  claim 1  wherein:
 said set of cross-members includes a first cross-bearer, said first cross-bearer having a first web and a second web, said first and second webs being spaced apart; 
 said first and second webs of said first cross-bearer having upper edges welded to an underside of said floor sheet; 
 said set of stringers including a first stringer; 
 said first stringer is a first channel having a first leg, a second leg and a back joining said first and second legs; and 
 said legs of said channel being welded toes-in to the underside of said floor sheet. 
 
     
     
         10 . The box car floor assembly of  claim 9  wherein a doubler is mounted to said first web of said first cross-bearer underneath said first stringer, and said doubler is welded to said back of said first stringer. 
     
     
         11 . The box car floor assembly of  claim 9  wherein said legs of said first stringer are splayed apart such that the toes of said legs are separated by a first distance; said back of said first stringer has a width; and said first distance is greater than said width. 
     
     
         12 . The box car floor assembly of  claim 9  wherein:
 said box car floor assembly includes a second stringer; 
 said second stringer is a second channel corresponding to said first channel of said first stringer; 
 said first stringer is mounted laterally inboard of said second stringer; 
 said first leg of said first channel of said first stringer is an inboard leg; 
 said second leg of said first channel of said first stringer is an outboard leg; 
 said second stringer has a respective inboard leg and a respective outboard leg; 
 said first channel has toes of said first and second legs thereof that are welded to the underside of said floor sheet, said toes being separated by a first distance; 
 said second channel has toes of its respective inboard and outboard legs welded to the underside of said floor sheet, said second channel being distant from said first channel; 
 there being a second distance between the outboard toe of said first channel and the inboard toe of the second channel; and 
 said second distance is in the range of 70% to 130% of said first distance. 
 
     
     
         13 . The box car floor assembly of  claim 9  wherein said floor assembly has a longitudinal centerline and a set of out-of-plane stems located between said centerline and a laterally outboard margin thereof, two of said out-of-plane stems being defined by said first and second legs of said first stringer, that set of out-of-plane stems dividing said floor sheet into a number of segments, and each of said segments has an unsupported span distance between two adjacent ones of said stems, and each of said distances is in the range of 11/16 to 21/16 of the average of said distances. 
     
     
         14 . The box car floor assembly of  claim 9  wherein:
 said floor assembly has a longitudinal centerline; 
 said floor assembly includes a center sill that extends downwardly from said floor sheet; 
 said center sill has a first web that is welded to said floor sheet and extends downwardly out-of-plane relative thereto;
 said floor assembly includes a second stringer; 
 said second stringer is a second channel corresponding to said first channel of said first stringer; 
 said first stringer is mounted laterally inboard of said second stringer; 
 said first leg of said first channel of said first stringer is an inboard leg; 
 said second leg of said first channel of said first stringer is an outboard leg; 
 said second stringer has a respective inboard leg and a respective outboard leg; 
 said first channel has toes of said first and second legs thereof that are welded to the underside of said floor sheet; 
 said second channel has toes of its respective inboard and outboard legs welded to the underside of said floor sheet, said second channel being distant from said first channel; 
 a first segment of said floor sheet is defined between said first web of said center sill and said inboard toe of said first channel; 
 a second segment of said floor sheet is defined between said first and second toes of said first channel; 
 a third segment of said floor sheet is defined between said outboard toe of said first channel and said inboard toe of said second channel; 
 a fourth segment of said floor sheet is defined between said first and second toes of said second channel; and 
 each of said segments has a width in the transverse direction; 
 said widths have an average size; and 
 each of said widths lies within the range of 70% to 130% of said average size. 
 
 
     
     
         15 . The box car floor assembly of  claim 14  wherein said widths of said segments are substantially equal sized. 
     
     
         16 . The box car floor assembly of  claim 15  wherein:
 said floor assembly has a marginal edge most laterally distant from said centerline, and a reinforcement channel defined along said marginal edge; 
 there is a fifth segment of said floor sheet between said outboard toe of said second stringer and said reinforcement channel; and 
 said first, second, third, fourth and fifth segments are substantially equally sized. 
 
     
     
         17 . The box car floor assembly of  claim 1  wherein:
 said floor assembly has a marginal edge most laterally distant from said centerline, and a reinforcement channel defined along said marginal edge; and 
 tie-down fittings are mounted in said reinforcement channel. 
 
     
     
         18 . The box car floor assembly of  claim 17  wherein said reinforcement channel is welded underneath said floor sheet and said floor sheet has cut-outs through which to obtain access to said tie-down fittings. 
     
     
         19 . A railroad car floor assembly, said floor assembly including:
 a floor sheet having a lengthwise direction and a transverse direction;   an array of cross-members, said cross-members being mounted to extend in said transverse direction;   an array of stringers mounted to said cross-members, said stringers being mounted to run in said lengthwise direction;   said floor sheet having an upward facing lading supporting surface; and   said array of stringers being mounted flush with said array of cross-members.   
     
     
         20 . A railroad car floor assembly, said floor assembly including:
 a floor sheet having a lengthwise direction and a transverse direction;   an array of cross-members, said cross-members being mounted to extend in said transverse direction;   an array of stringers mounted to said cross-members, said stringers being mounted to run in said lengthwise direction;   said floor sheet having an upward facing lading supporting surface;   said floor sheet defining an uppermost flange of said cross-members; and   said floor sheet defining an uppermost flange of said stringers.   
     
     
         21 . A method of assembly of a railroad car floor assembly, the floor assembly including a floor sheet having a lengthwise direction and a transverse direction, the floor sheet having an upper surface upon which to support lading; an array of cross-members; and an array of stringers, said method including:
 welding the stringers to an underside of the floor sheet with welds running in the lengthwise direction of the floor sheet; and   welding the cross-members to the underside of the floor sheet and to the stringers with welds running in transverse to the floor sheet.   
     
     
         22 . The method of  claim 21  wherein said method includes placing the floor sheet upside-down prior to welding the stringers thereto. 
     
     
         23 . The method of  claim 21  wherein there is a straight-through center sill having a pair of spaced apart webs; and the method includes positioning the center sill in a lengthwise orientation relative to the floor sheet and welding said webs to the floor sheet with welds running in the lengthwise direction. 
     
     
         24 . The method of  claim 21  wherein the floor sheet is a non-nailable sheet and said method includes welding the cross-members and the stringers to the floor sheet such that said stringers and said cross-members mount to the floor sheet flush with each other. 
     
     
         25 . The method of  claim 21  wherein the cross-members have cross-member webs that stand downwardly of the floor sheet and the method includes providing the cross-member webs with accommodations to permit the stringers to pass thereacross unobstructed. 
     
     
         26 . The method of  claim 25  wherein the stringers have a web that stands away from the floor sheet and a flange mounted to the web, the flange standing spaced distantly from and in opposition to the floor sheet, and the method includes providing a doubler plate that mounts to a face of the web of the cross-member, and welding a margin of the doubler to the flange of the stringer distant from the floor sheet. 
     
     
         27 . The method of  claim 21  wherein the stringers have a channel shape, and the method includes mounting the channel shape toes-in to the floor sheet. 
     
     
         28 . The method of  claim 27  wherein the method includes spacing said stringers cross-wise relative to the floor sheet to leave equal un-supported spans of the floor sheet. 
     
     
         29 . The method of  claim 27  wherein there is a first gap distance between the toes of each said stringer, and a second gap distance between the toes of one stringer and the nearest toe of the adjacent stringer and the method includes spacing said stringers across the floor sheet such that the first gap distance is in the range of 70% to 130% of the second gap distance. 
     
     
         30 . The method of  claim 21  wherein the method of assembly is a method of assembly of a of a railroad box car floor assembly, the floor assembly including a center sill having a pair of spaced apart center sill webs that extend downwardly from the floor sheet; the stringers having a channel shape, the channel shape having toes and a back the channel shape having a first gap between the respective toes, and the method includes:
 placing the floor sheet upside-down; 
 welding the webs of the center sill to the underside of the floor sheet with welds running in the lengthwise direction; 
 welding the stringers in a toes-in orientation to the underside of the floor sheet with welds running in the lengthwise direction; 
 dividing the unsupported spans of the floor sheet into a set of segments that have a size in the range of 70% to 130% of the size of said first gap; 
 providing the cross-members with a pair of spaced apart webs that stand away from the floor sheet, and providing the webs with accommodations that permit the stringers to pass uninterrupted through those webs; 
 welding the webs of the cross-members to the underside of the floor sheet with welds running in the transverse direction; 
 welding web separators within the center sill to provide web continuity for the webs of the cross-members through the center sill; 
 welding web doublers to the outsides of the cross-member webs and to the backs of respective stringers; and 
 turning the as welded assembly upside right.