This bogie model represents the first variants of the UFB bogies with tilted primary spring. This is a replacement bogie for the MTB made TT scale M41 locomotive (which models a later bogie variant with vertical primary springs). It is optimised for 3D printing, recommended layer height: 15 microns.To replace the bogie sideframe, just remove the factory sideframe and place the 3D printed one in it's place. Secure with glue if needed. No further modifications are required.