A Driving Van Trailer (DVT) is a British purpose-built control car railway vehicle that allows the driver to operate with a locomotive in push-pull formation from the opposite end of a train. A key benefit of operating trains with DVTs is the requirement for fewer locomotives; for example, a second locomotive would otherwise have to join at the other end of the train after arrival at terminal stations to lead the train's onward journey.
Unlike many other control cars, DVTs resemble locomotives, specifically Class 90 for the 82/1 mark 3 series and Class 91 for the 82/2 mark 4 series; thus when the train is operating in push mode, it does not appear to be travelling backwards. The vehicles do not have any passenger accommodation due to health and safety rules in place at the time of construction that prohibited passengers in the leading carriages of trains that run faster than 100 miles per hour (160 km/h).[citation needed] Historically, it was believed that a train would be unstable at high speeds unless pulled from the front; however, extensive testing and the experience of high speed trains with central power cars, such as the InterCity APT and the Eurostar, have since altered this view.
Development
The DVT concept is similar to the Mark 2DBSO 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 Mark 2 and Mark 3 coaches. The second design has a narrower profile, similar to Mark 4 coaches, which would enable it to be converted to tilting operation if required in the future. 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 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. The Class 86 and Class 87 locomotives had to be retrofitted with RCH cables, replacing the older multiple working jumpers that some of them had been fitted with.[1]
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 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 and now Neville Hill) are situated at the north end of King's Cross and Leeds stations respectively, allowing easy changeover.
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; however, if the DVT is leading, it will be necessary to uncouple the locomotive and attach it to the front of the train.
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.[2] 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 Class 19 locomotive.
Mark 3 DVT
82132 of NXEA in debranded "One" livery departing Stratford on the GEML, 2/08The driver's desk of a Mk3 DVT
They also operated between Wolverhampton and Shrewsbury, and between Crewe and Holyhead, hauled by Class 47 diesel locomotives. The 47s always operated leading the train because these locomotives were not fitted with push-pull equipment.
Following the loss of a Class 390 Pendolino in the Grayrigg derailment, a Mark 3 set with a Driving Van Trailer was leased with a Class 90 hired from English Welsh & Scottish as required. In 2008, Virgin looked at leasing two Class 180[5] but decided to retain the Mark 3 set. Nicknamed the Pretendolino, this received re-upholstered seating, power points, wi-fi and a full Virgin external repaint at Wabtec, Doncaster in 2009.[6] Virgin used this set with a Class 90 locomotive, hired from Freightliner, on a Euston to Crewe (via Birmingham) service on Fridays only until December 2012. From 9 December 2013, it was utilised to operate a London Euston - Birmingham New Street train on Thursdays and Fridays only, until its withdrawal in October 2014.
In January 2020, the first Class 745selectric multiple units entered service.[8] The locomotive-hauled sets were withdrawn from service, with the last set running on 24 March 2020.[9]
The standard practice was for the DVT to be marshaled at the northern end, adjacent to the standard class carriages, to facilitate easy changeover of locomotives at Norwich Crown Point depot.[10]
Wrexham & Shropshire started operating push-pull services with DVTs in October 2008 between London Marylebone and Wrexham General, with Mark 3s and Class 67 diesel locomotives. This followed the start of the service in April 2008, with Class 67s operating in top and tail formation. The DVTs required modification to work with the Class 67, involving adding a notched power controller as is used in the locomotive and a 27 wire jumper cable as used on the locomotives, which is known as the AAR multiple-working system. They were renumbered 82301 to 82305.[18][19]
With the reduction in service levels from December 2010, a Mark 3 set was hired to Chiltern Railways to operate a Birmingham Moor Street to London Marylebone peak-hour service.[20][21] The standard practice was for the DVT to be marshaled at the southern end.
Chiltern Railways
After Wrexham & Shropshire ceased in January 2011, its fleet of five DVTs were transferred to fellow DB Regio UK company Chiltern Railways and started operating on London Marylebone to Birmingham Snow Hill services with Mark 3s.[22] They were modified to work with the power doors that were fitted to the Mark 3 coaches and to have a generator fitted to enable Electric Train Supply and compressed air to be provided to the coaches when the locomotive is not running, such as when in a terminus station and when stabled.[23][24] Initially operated with Class 67s, they have been operated with Class 68s since December 2014.[25] Some peak services were extended to Kidderminster. A sixth DVT (82309) was leased to operate with a Mark 3 set on a peak hour service from London Marylebone to Banbury. The standard practice is for the DVT to be marshaled at the southern end.
Network Rail
In early 2013, several DVTs, including 82111, 82124, 82129 and 82145 were acquired by Network Rail and modified to work with diesel locomotives for use on test trains. Part of the modification work includes the integration of a diesel generator to provide power for on-board systems.[26]
With the delivery of Class 800 and Class 801, mass withdrawals commenced in May 2019.[47] Originally it was proposed that all the InterCity 225 sets be withdrawn by the end of 2020, but LNER decided to retain 10 sets until at least December 2021 to allow it to increase services.[48] A limited number of sets will continue to operate in the new May 2022 timetable.
Grand Central
Grand Central would have used Mk4 coaches and DVTs on London Euston to Blackpool North services with Class 90 locomotives hauling six-carriage sets;[49][50][51] however, these services were permanently abandoned on 10 September 2020, due to the negative effects of COVID-19 on passenger numbers[52] All five were sold to Transport for Wales in 2021.[53]
^The track obstruction by a road vehicle and subsequent train collisions at Great Heck 28 February 2001 (Report). Health and Safety Executive. February 2002. p. 15. ISBN0-7176-2163-4.
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