The file 'A Modified Boxcab In Order To Fit With A BTTB Mechanics TT Scale 3D Printer Model' is (stl) file type, size is 3.7MB.
I made a little adaptation of this boxcab:https://cults3d.com/en/3d-model/art/n-scale-boxcab-body-for-kato-11-109And then I can fit it to a BTTB mechanics (SNCF startset).