Two railcars or locomotives that are semi-permanently coupled together and operate as a single functional unit. They often share a single brake valve system or drawbar, meaning they cannot be separated during normal switching operations and must be shopped together.
Heard on the job
That intermodal twinset has a bad flat spot on the trailing truck, so we'll have to bad-order both platforms.
Related terms
Consist
The makeup of a train, listing its locomotives and cars in order with weights, loads and hazmat.
Multiple unit
A train configuration where several self-propelled cars are coupled and controlled from a single cab.
Drawbar
A solid metal beam or assembly that connects railcars or locomotives together to transmit pulling force.