Re: Bulkhead flat 115757 (Southern series 115750-115774)
An interesting car! The series was modified by Evans and renumbered in 1964 under Special Car Program (SCP) 754 from wood racks 120998-122997. They were 50-ton capy cars built in 1938-39 per diagram book page F-2111. (Available from the SRHA grab but there are not many left.)
The 120998-122997 cars were themselves rebuilt from 175000-176344 50-T D.D.B. gons.
The SRHA drawing list shows three drawings used for the modification. I’ll check the microfilm but they have not been scanned yet. (Scott, a good project on our next trip to Chattanooga.) The rebuild drawings include: SF-21257, -21316 and -21877. The last drawing shows the side sill modification. The photo of 115757 shows the plate welded along the entire side sill. (Note the photo also shows an 8-38 blt date that corresponds to the 120998-122997 series wood racks.)
With these cars’ “pedigree” there are a lot of drawings but I expect modeling one would be mostly a scratch-built project.