A barrier vehicle is a type of train car used to connect two other cars that do not have couplings and other systems that would normally be compatible. There are a number of different types of barrier vehicles that can be used, with some only intended to connect cars with different types of couplings, and others that connect cars that also have different braking systems and serve to ensure the systems will function together properly. A barrier vehicle can often be seen on different types of trains, and may be recognized on passenger trains by its lack of windows.
The basic function of a barrier vehicle on a train is to allow two train cars, or coaches, with different coupling types to connect together. A coupling is the area at the back and front of a train car that can be connected to another car, allowing the cars to be connected and make up an entire train. Over the years, different types of couplings have been developed and used to connect multiple cars together. While a coupling adapter can potentially be used in some situations, it can often be more efficient, or necessary, to use a barrier vehicle instead.
Also referred to as a translator vehicle, or a barrier coach or translator coach in the UK, a barrier vehicle can serve a number of purposes. When acting only as a connecting car between two other cars that would not normally be able to connect together due to different types of couplings, then it is often referred to as a match wagon or match truck. This type of barrier vehicle will have one type of coupling at one end and another type of coupling at the other end. The match truck can then be connected to two cars with different coupling types, creating a sturdy connection.
A barrier vehicle that serves to not only connect cars with different coupling systems, but also other types of systems that may not be compatible, is referred to as a translator vehicle or coach. This type of barrier vehicle connects different coupling types and allows cars with different mechanical systems to properly function together. Two cars with different braking systems, for example, might use a translator vehicle to serve as a coupling connector and to allow the brakes to function properly between the different cars. This can be necessary for using various cars and coaches with different hardware and systems on a single train.