These vehicles were supplied to the Weston Clevedon and Portishead Railway and served for many years providing a cheap to operate passenger service.
The kit bodyshells are designed to take 0.8mm shank brass buffers (not supplied). You will also need some laddering and wire to make the roof rack and access on the driving car.
The prints represent the trailer in its later form. The railcar itself includes the optional external fuel tank which can be fitted to represent the later arrangements if so desired.
You should receive both body shells and the small fuel tank part. If you only get two bodyshells please talk to Shapeways.