|British Rail Class 444 Desiro|
| South West Trains Class 444 Desiro 4440030 sparks through St Denys with a London Waterloo bound service. |
|In service||21 April 2004 - Current|
|Built at||Vienna, Austria|
|Number built||45 trainsets|
|Formation||5 cars per trainset|
|Capacity||299 standard, 35 first|
|Operator||South West Trains|
|Maximum speed||100 mph (Template:Convert/outsep)|
|Electric system(s)||750 V DC third rail|
|Current collection method||contact shoe|
|Braking system(s)||Air, regenerative|
The British Rail Class 444 Desiro electrical multiple units were built in Germany by Siemens AG from 2003-04. Forty-five of these units were built for express services for South West Trains. The Siemens "Desiro UK" family also includes units of Classes 185, 350, 360, 380, and 450.
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 Vienna 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 reduce the time taken for new trains to 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 entered service faster than its competitors, but the trains still suffered from teething problems. Units are formed of five cars or coaches, 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 DMSO+TSO+TSO+TSRMB+DMCO. Individual vehicles are numbered as follows.
- 63801-63845 - DMCO
- 67201-67245 - TSRMB - fitted with Pantograph Well
- 67101-67145 - TSO
- 67151-67195 - TSO
- 63851-63895 - DMSO
Units have end-gangways, which allows people to move between units when they are used in multiple on services. Trains are limited to a 10-coach length (i.e. two 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. Each five car unit has a first class section taking up just over half of one car at one end; first class seats have BS 1363 sockets providing AC power suitable for laptops or mobile phone charges, while the car at the other end is standard class throughout and appears ordinary but has BS1363 sockets under the tables. Like all new build third rail stock in the UK, one coach in each unit is fitted with a recess for a pantograph. This allows for a future conversion to AC overhead power.
Class 444 trains have been awarded with the "Golden Spanner 2010" as Great Britain's most reliable trains by the Modern Railways journal. During twelve months, the vehicle feet operated by SWT has set a new reliability record of almost 89,000 kilometres per technical delay. 
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 Central, 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, some were allowed to remain operational until May 2005 as the last replacement Desiros came into service. Initially, the Class 444 units were primarily used on the Portsmouth direct services, allowing the Wessex Electric units to be used on the Weymouth line. The Class 444 units were also used regularly on Sunday-only Bournemouth stopping services, Waterloo to Southampton services and the Brockenhurst to Wareham shuttle service. Previous power limitations on the line west of Poole meant that units were not permitted to run west of the town; the power limitations have since been lifted. During 2007, the Class 444 units replaced the Wessex Electrics on the Weymouth line. Some 442 diagrams were taken over by 444s as early as November 2006 with the final 442 being withdrawn from passenger service in February 2007. Class 444s transferred to the Weymouth line were replaced on Portsmouth services by Class 450 Desiros which became available after the reintroduction of the Class 458 units on the Waterloo to Reading line. The decision to transfer many 444 units to the Weymouth line was not a popular one. Portsmouth line passengers protested over the use of class 450s on some services  while there were complaints that the 444s were inferior to the units they replaced on the Weymouth line. Class 444s are currently used on the following services:
- Waterloo to Alton (peak services)
- Waterloo to Basingstoke (peak services)
- Waterloo to Poole (shared with Class 450)
- Waterloo to Portsmouth Harbour via Guildford (shared with Class 450)
- Waterloo to Portsmouth Harbour via Basingstoke and Fareham (shared with Class 450)
- Waterloo to Weymouth via Winchester and Southampton Central
In June 2007, it was reported in the Ipswich Evening Star that the Network Rail's Greater Anglia area Rail Utilisation Strategy was 'touting' the possibility of introducing a train based on the class 444 on the London - Ipswich - Norwich railway line.
|Class||Operator||No. Built||Year Built||Cars per Set||Unit nos.|
|Class 444||South West Trains||45||2003-2004||5||444001 - 444045|
- ↑ 1.0 1.1 1.2 Desiro UK Class 444 Multiple Unit - Siemens Mobility. Page 38. Retrieved 19 July 2011.
- ↑ Siemens Desiro Class 444 wins award as most reliable train. transportweekly.com (2011-01-12). Retrieved on 2011-01-15.
- ↑ Commuter protest over rail seats. BBC News (2007-01-22). Retrieved on 2008-05-10.
- ↑ Councillor Sceptical at Train Service Changes. Bournemouth Daily Echo (2007-01-21). Retrieved on 2008-05-10.
- ↑ Rail Downgrade Feared by Ipswich. Ipswich Evening Star (2007-06-19). Retrieved on 2008-05-10.