Mk3 DVT
The Mk3 Driving Van Trailers (DVT) were built primarily for operation with the then new class 90 locos for push-pull duties on the WCML. Their use was eventually extended to the class 86 and 87's after these locos had undergone minor modifications to make them suitable for this role. The DVT's were designed such that they could operate the locomotives remotely using a Time Division Multiplex (TDM) system of control by which 'signals' are sent through the standard Railway Clearing House (RCH) lighting jumper cables to operate the controls of the locomotive.
I remember undertaking TDM trials on the WCML with a couple of class 85s and a rake of Mk2 coaches, mainly between Crewe Basford Hall and Stafford. The locos were not permanently fitted for TDM just 'jury-rigged' and monitored.
Later when the Mk3 DVTs arrived they were also trialled in a similar way but with a class 86 which would be then have been coming off works fitted with TDM kit.
86248 with 82103 & 82105,
Top & Tailing a TDM Test Train at Stafford Station on the 1st September
1989 John Hill |
Although this system worked well in theory the practice was somewhat fraught and the sight of a locomotive marshalled next to the DVT after a TDM failure was quite common in the early days. Later the fleets of Mk2 and Mk3 coaches were re-wired with the standard UIC screened cables as fitted to the Mk4 coaches and the operation improved markedly.
The M3 DVT's were unusual in that they were the only vehicles to be fitted with the T4 bogie which was a contender for the Mk4 coaches. Nuff said!
With the introduction of the full Pendolino services their days on the WCML seemed to be over but a number of them have been acquired by other new operators and charter services. Until quite recently (2014) VWC still had a class 90 and DVT substituting for the damaged Pendolino which was involved in the derailment at Lambrigg.
Amongst their alternative operators have been Scotrail on the North Berwick services (82106, 82109, 82112, 82120 and 82132) between May 2004 and September 2005.
EWS (DB Schenker) have 82146 on their company train (repainted in silver),
Wrexham and Shropshire used them with class 67's and Hull Trains did use one with the class 86 when it deputised for the damaged class 222 unit, although these have now ceased operation. Chiltern now use them on their 'InterCity' trains between Marylebone and Birmingham.
The main user is still NX East Anglia (formerly 'One railway') who have15 of them with their Mk3 rakes and class 90 locomotives.
It looks like they will (rightly) be with us for a while yet.
Click on the picture for a bigger image - photos are the author's unless otherwise stated.
More pictures will be added as time permits