The British Rail Class 444 (or 5Des) "Desiro" electrical multiple units were built by Siemens AG from 2003-04. Forty-five of these units were built for express services for South West Trains. The "Desiro" family also includes units of Classes 350 , 360 and 450.

Description

At the dawn of the 21st century, as part of its franchise agreement, South West Trains (SWT) was required to order new trains to replace the old slam-door stock of Classes 411, 412, 421 and 423. Therefore, in April 2001 an order was placed with Siemens AG for 785 vehicles. This order was originally to be split as 100 four-car Class 450/0 outer-suburban units, 32 five-car Class 450/2 inner-suburban units and 45 five-car Class 444 express units.

The Class 444 fleet was built by Siemens at its Wien plant in Austria. Before shipping to Britain via the Channel Tunnel, units were extensively tested at the test-track at Wildenrath . This extensive testing procedure was performed as in attempt to increase the speed at which trains could enter service, by ironing out any problems beforehand. Many other designs of new train, such as the Bombardier Class 375 and Alstom Class 458 units, had been plagued by problems and poor reliability. The "Desiro" fleet did enter service faster than its competitors, but units still suffered from teething problems.

Units are formed of five-cars, and are numbered in the range 444001-045. Each unit is formed of two outer driving motors, two intermediate trailers, and an intermediate buffet coach. The description of this formation is DMCO+TSO+TSO+TSRMB+DMSO. Individual vehicles are numbered as follows.

• 63801-63845 - DMCO
• 67101-67145 - TSO
• 67151-67195 - TSO
• 67201-67245 - TSRMB
• 63851-63895 - DMSO

Units have end-gangways, which allows passengers to move between units when they are used in multiple on services. Trains are limited to a 10-coach length (i.e. 2 units) as longer trains cannot be accommodated in stations. The fleet is painted in SWT's express livery of white, with a blue window band, and red/orange swishes at the cab ends.

Operations

The first Class 444 units entered service with SWT in early 2004. As part of their launch into traffic, unit no. 444018 was named "The Fab 444" at a ceremony at London Waterloo.

The units were introduced on services from London Waterloo to Portsmouth Harbour via the Portsmouth Direct Line. Units were also used on some services on the South Western Main Line to Southampton, Bournemouth and Weymouth. This allowed the withdrawal of the final 4Cep units by mid-2004, and inroads were made to the 4Bep, 4Cig and 4Vep fleets.

It was originally hoped that the final slam-door units would be withdrawn by 31 December 2004. However, they are now expected to remain until May 2005. Once the full Class 444 fleet is in service, it is planned that they will be primarily used on the Portsmouth direct services, allowing the Wessex Electric units to be used on the Weymouth line. Due to power limitations, the Desiros currently cannot operate in multiple west of Poole.