Roadrailer

In railroad terminology a roadrailer is a highway trailer that is specially equipped for use in railroad intermodal service. The advantage of using roadrailers is that due to their construction, the trailers can be pulled directly behind other freight equipment without the use of trailer flatcars.

Roadrailers first appeared on American railroads in the 1950s. The trailers were built with integrated railroad wheelsets that could be lowered into position when the trailer was pulled behind a train. More modern roadrailers do not include integrated railroad wheels, but ride on specially manufactured bogies that do double-duty serving as articulation points between multiple trailers in a train.