GWR railcar no 18
After the successful introduction of streamline diesel railcars by the GWR in the 1930s, it was decided to built some which could haul ,more coaches or wagons.
No 18 was a prototype, with buffers & draw gear for hauling vans . After tests it was mainly used on the Lambourne branch line from Newbury, and was withdrawn in 1957.
requires chassis and interior
TT120 (1/120 scale)
more info about GWR railcars here
https://en.wikipedia.org/wiki/GWR_railcars
https://www.greatwestern.org.uk/aec1.htm
more 3d printed models from Recreation21 here
https://www.rue-d-etropal.com/3D-printing/3d_printed_designs.htm