I recently got the chassis parts gathered for the 2 RPP SD38 shells I had. Athearn SD45 frames and SD6 trucks are used. The frames needed to be milled to fit the shells. The rear frame bolster had to be narrowed and some of the raised lip on the top of the frame removed. Some of the raised lip on the top of the frame needed removed on the front to clear the walkway. .050" was milled off the coupler pocket and the pad was shortened by .070". The mounting holes were relocated to mount a KD 30 series couplers and draft gear. The shells are held on by the 30 series draft gear.