Now in use on some major railroads, the RoadRailer(R) can be operated as a truck trailer or a rail car using the retractable running gear. A special coupler is used so that RoadRailers are run as unit trains. Kits include unpainted plastic and metal parts.
 
This unit is used as an idler between the loco and other RoadRailer units. It has a standard coupler at the front, and the special RoadRailer coupler at the rear.