Driving van trailer

British Rail DVT
A Virgin Trains Mark 3 DVT at Birmingham New Street.
In service	1988 – present
Manufacturer	BREL, Metro-Cammell, Breda (Under sub-contract)
Family name	British Rail Mk3 (82101–82152) British Rail Mk4 (82200–82231) British Rail Mk3 (82301–82309) Refurbished
Constructed	1988
Number built	Mk3: 52 vehicles Mk4: 32 vehicles
Number scrapped	Mk3: 6 Mk4: 1
Fleet numbers	82101–82152 82301-82309 82200–82231
Operator(s)	Chiltern Railways DB Schenker Abellio Greater Anglia Virgin Trains East Coast Arriva Trains Wales Network Rail Direct Rail Services
Specifications
Car length	18.83 m (61 ft 9 in)
Width	2.71 m (8 ft 11 in)
Height	3.88 m (12 ft 9 in)
Maximum speed	Mk3: 110 mph (177 km/h) Mk4: 140 mph (225 km/h)
Weight	43.7 t (43.0 long tons; 48.2 short tons)
Braking system(s)	Air
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge

A Driving Van Trailer (DVT) is a purpose-built control car railway vehicle that allows the driver to operate a locomotive at the opposite end of a train. Trains operating with a DVT therefore do not require the locomotive to be moved around to the other end of the train at terminal stations. Unlike many other control cars, DVTs resemble locomotives (specifically Class 91) and thus when the train is operating in "push" mode it does not appear to be travelling backwards. The vehicles have no passenger accommodation due to rules in place at the time of building that prohibited passengers in the leading vehicles of trains that travel at more than 100 miles per hour (160 km/h).

On the InterCity 225 (IC225) sets operating on the East Coast Main Line (ECML) the Mark 4 DVTs and locomotives operate in push-pull formation utilising a time-division multiplexer to send control signals along specially screened cables which run the length of the train. The locomotives usually face away from London, only being changed occasionally in rare circumstances.

On the original Mark 3 DVTs, which operated on the West Coast Main Line (WCML), the intention was to use the RCH jumpers to carry the signals therefore allowing the same cables to be used for lighting and the public address system, as well as driver-guard signalling. However this proved to be very troublesome in service and eventually the rakes of coaches on the WCML were re-wired with specially screened cables exclusively for the TDM system.

In addition to the driver's cab, some DVTs have luggage and cycle storage space and a guard's office.

When a train is operated by a DVT, the control signals are encoded and multiplexed onto the cables by the TDM equipment in the DVT. At the locomotive, these signals are demultiplexed by the TDM equipment, and the signals are used to control the locomotive. The air braking system is operated directly from whichever cab the driver is driving from. If the TDM fails and cannot be reconfigured, the train may still operate, but if the DVT is leading, it will be necessary to uncouple the locomotive and attach it to the front of the train.