Abstract: A railway car underframe includes a centersill having a central section and opposite end sections. The sill includes spaced vertical walls, and upper and lower walls which are slotted and in registry the length of the central section, and which form in cross section a spaced I-beam construction. The construction provides a sill having high torsional flexibility which is necessary to accommodate the railway car to track conditions tending to derail the car when single axle trucks with two wheels are utilized.

Abstract: A railway car underframe includes a center sill having a central section and opposite end sections. The sill includes spaced vertical walls, and upper and lower walls which are slotted in registry the length of the central section, and which form in cross section a spaced I-beam construction. The construction provides a sill having high torsional flexibility which is necessary to accommodate the railway car to track conditions tending to derail the car when single axle suspensions with two wheels are utilized. The sill also includes a separator in the form of a channel which includes flanges at its sides which are secured to the vertical walls of the sill. The separator extends substantially the length of the slots and is effective to resist lateral forces tending to buckle during operation while not adversely affecting the high torsional flexibility which is required in the sill structure.