This type of train coupler is widely used for passenger trains in Japan.

If you have 3D printers, please print Part00to03.stl, Part05.stl and Part06.stl.
If you feel somewhat wrong or dissatisfaction, or you have only milling machines, please make Part00.stl, Part01.stl to Part06.stl and assemble
them using glue.
To complete assembling, please prepare two brass rods of 2mm diameter and 40mm length.