This motorail terminal is built with two sets of #4544 Car Transporters and nothing else except a roadplate. It uses almost every single piece from the two sets to build a ramp and loading platform for cars to drive onto the waiting transporters. The transporters are unmodified and the gates at each end can be lowered and connected together so that cars can drive from one transporter to the next.
Officially, the #4544 set was discontinued several years ago but it is still available from LEGO Shop at Home.