doublecar

Doublecar is a term used in transportation to describe a vehicle or train configuration consisting of two connected car bodies. It is not a formal, standardized designation, and its meaning varies by mode and region.

In trains and trams, a doublecar or double-car unit refers to a pair of passenger cars coupled together to operate as a single train unit. This arrangement increases passenger capacity and can offer operational flexibility, particularly on lines with platform length suited for two cars or during peak demand. In some systems, such paired sets are operated with a single driving cab at one end, or with cabs at both ends to allow bidirectional operation. The term may be used interchangeably with two-car formation, two-car train, or MU (multiple unit) set, though many operators reserve MU for trains with integrated traction and braking control across cars.

In automotive or concept design, doublecar can describe ideas where two car bodies share a frame or connect in tandem. Such designs have appeared in concept studies or speculative proposals but are rare in production vehicles.

The term is largely descriptive and context-specific; it is not tied to a single standard or technical specification. Related concepts include two-car trains, multiple-unit trains, articulated trains (which share a common structure), and bi-car configurations. Etymologically, the term derives from combining “double” with “car” to denote two linked cars.