I designed and tested prewar to postwar coupler adapters then adjusted and tested for quite a few iterations. These are for the HIgh and low prewar box or automatic couplers. I have uploaded them to the 3d Catalog, the instructions have full details. I have been running them. A lot more work finding just the right sizes and fit than I thought.. But they work! Some pictures.
Version 1 for the Higher couplers. The one for the lower coupler is similar.
Version 2, before coupling. There is normally some slack in the prewar couples in Z and when it pulls, the prewar coupler tends to pull up a little. This version not supported in the lower prewar couplers.
