SECR railmotor push-pull coach
These coaches were originally built by the SECR as steam railmotos, but in the 1920s, they were converted into 2 pairs of push-pull coaches and 2 sets of non push-pull articuated coaches. They lasted in this state till the 1950s.
One coach in each set had its luggage/guard section conveted to passenger use, initially 1st class in the push pull sets.
This is one of the converted coaches, which was used in push pull sets, and had 1st class compartment .
Requires chassis.
Scale O (1/43.5, 7mm/ft)
more info about the SECR here
https://www.southeasternandchathamrailway.org.uk/shorthistoryofsecr.html
more 3d printed models from Recreation21 here
http://www.rue-d-etropal.com/3D-printing/3d_printed_designs.htm