Smokey Mountains Seaboard Air Line Turtleback boxcars we’re in S scale only I believe, I know he hasn’t done O scale yet.
Zach Pabis, who has 3D printed the SAL 2028 motorcar in HO and O, has some data to do the SAL Turtleback car, but nothing definite yet.
Nobody has done a correct SAL car yet and they are not the same as the PRR or B&O cars. I have 2 of the MTH round roof cars and they are close to the B&O cars. I think the Lionel cars are close to the PRR cars.