Editing Driving Van Trailer (section)

==Development==
The DVT concept is similar to the [[British Railways Mark 2|Mark 2]] [[Driving Brake Standard Open|DBSO]] but, unlike its predecessor which was rebuilt from existing stock, it was a new build vehicle manufactured specifically for this purpose. The first design of DVT was designed to match [[British Rail Mark 2|Mark 2]] and [[British Rail Mark 3|Mark 3]] coaches. The second design has a narrower profile, similar to [[British Rail Mark 4|Mark 4]] coaches, which would enable it to be converted to [[tilting train|tilting operation]] if required in the future.{{citation needed|date=February 2024}} The nose of the vehicle was styled to closely resemble the Class 90 and 91 locomotives that they were paired with.

The original Mark 3 DVTs, which operated on the [[West Coast Main Line]], used the [[Railway Clearing House|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-[[Conductor (transportation)#Train guard|guard]] signalling. The {{brc|86}} and {{brc|87}} locomotives had to be retrofitted with RCH cables, replacing the older multiple working jumpers that some of them had been fitted with.<ref>{{cite web |url = https://www.aclocogroup.co.uk/history86.php |title = Class History - AL6 / 86 |publisher = [[AC Locomotive Group]] |archive-url = https://web.archive.org/web/20180908164704/https://www.aclocogroup.co.uk/history86.php |archive-date = 8 September 2018 }}</ref>

The [[InterCity 225]] sets operate on the [[East Coast Main Line]]; the Mark 4 DVTs and locomotives operate in push-pull formation utilising a [[time-division multiplexing|time-division multiplexer]] to send control signals along specially screened cables which run the length of the train. The locomotives usually face north, away from London, only being changed occasionally in rare circumstances; this is because the Class 91 depots (formerly [[Bounds Green TMD|Bounds Green]] and now [[Neville Hill TMD|Neville Hill]]) are situated at the north end of King's Cross and Leeds stations respectively, allowing easy changeover.{{citation needed|date=February 2024}}

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 [[Railway air brake|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; however, if the DVT is leading, it will be necessary to uncouple the locomotive and attach it to the front of the train.{{citation needed|date=February 2024}}

In addition to the driver's cab, some DVTs have luggage and cycle storage space and a guard's office. One DVT was fitted with a traction gel applicator.<ref>{{cite journal |date = November 2013 |title = Leaf it out! |url = http://www.rruka.org.uk |journal = Right Track |issue = 6 |pages = 5–91 |access-date = 10 May 2020 |archive-date = 22 January 2019 |archive-url = https://web.archive.org/web/20190122004105/https://www.rruka.org.uk/ |url-status = live }}</ref> A number of Mark 3 DVTs have been fitted with generators to provide power to on-train equipment. One has been fitted with traction equipment, becoming the experimental [[British Rail Class 19|Class 19]] locomotive.<ref>{{cite web |url = http://www.artemisip.com/company/history/ |title = History |website = Artemis Intelligent Power |access-date = 21 August 2018 |archive-date = 27 January 2021 |archive-url = https://web.archive.org/web/20210127111135/http://www.artemisip.com/company/history/ |url-status = dead }}</ref><ref>{{cite web |url = https://www.railexpress.co.uk/in-the-october-issue-new-loco-takes-shape/ |title = New 'Loco' Takes Shape |date = 21 September 2017 |publisher = Rail Express |access-date = 21 August 2018 }}</ref>