Desiro: Classes 444 and 450

Desiro is the standard Siemens' commuter and regional multiple unit. It is of modular design and available in many forms, diesel and electric. Examples are at work in Germany, Greece, Hungary, Romania and Slovenia. Initial UK orders were ac electric units for work in West Yorkshire and on Heathrow Express. The UK design is significantly modified, in order to meet loading gauge constraints and use high station platforms. The characteristic Desiro nose is replaced by a much flatter front. A speculative order for 25 units was placed by Angel Trains in 2000. Further substantial orders followed and examples have been built for First Great Eastern and South West Trains, the latter being the only Desiros with end gangways. 31 five-coach units were ordered for South West Trains, but are being built as four-coach units for ac use by Silverlink and Central Trains.

The SWT units are being used to replace the Mark 1 units and class 458. Two versions have been built, class 444 for express services and class 450 for a wide range of stopping services. Due to prior testing on Siemens' test track at Wildenrath (near Mönchengladbach) units have entered service far more quickly and reliably than Junipers and Electrostars.

Units are formed of two driving motor coaches and two or three trailers. Carriage bodies are of aluminium and are mounted on SGP steel bogies. Both four- and five-coach units have four Siemens type 1TB2016-0GB02 asynchronous traction motors, with IGBT control. Pick up shoes are mounted on both bogies on the motor coaches. Westinghouse friction brakes are electrically activated. Dellner couplers are fitted at unit ends and semi-automatic couplings within units. Carriages have plug doors and are air-conditioned. Maximum speed is 100 mph.

The near vertical bodyside and large windows make these units far more light and spacious than other rolling stock built recently. Class 444 is easily the most impressive train to have entered service anywhere in the country since privatisation.

Class 444 are express units, intended for use principally between Waterloo and Portsmouth. Single leaf plug doors are at the carriage ends, except on the trailer buffet, and units are finished in a similar livery to class 442. Units have five coaches, driving trailer, two trailers, trailer buffet and driving trailer composite. Seating is 1+2 in first class and 2+2 in standard. The trailer buffet includes the guard's office, a disabled toilet and a standard toilet. The layout of this vehicle results in the external doors being set in from the ends, but not symmetrically. Both of the other trailers include a toilet and a bicycle rack. In the driving motor composite coach the first class saloon is adjacent to the driver's cab and the standard saloon is at the trailing end. The trailer buffet has a pantograph well.

444001 was under test at Wildenrath early in 2003. The first units arrived in the UK in November and entered service in April 2004.

• Built: Siemens, Wien
• Owner: Angel Trains
• Operator: South West Trains
• Seats: Driving motor 76; Trailer 76; Trailer 76; Trailer buffet 47 + wheelchair; Driving motor composite 35 1st, 24 standard.
• Number series: 444001 to 444045
• Named unit:
  444018 The Fab 444

Class 450 are four-coach units designed for outer-suburban and main line stopping services. Standard class seating is 2+3, and first class is 2+2. There is a toilet in both of the trailer coaches, that in the standard class vehicle being suitable for wheelchair users. The standard class trailer has a pantograph well. Livery is a new one for South West Trains, being mostly blue. 450001 commenced testing at Wildenrath in April 2002 and the first units arrived in the UK five months later. Passenger workings started in October 2003.

• Built: Siemens, trailers at Wien and motor coaches at Uerdingen (Krefeld)
• Owner: Angel Trains
• Operator: South West Trains
• Seats: Driving motor standard 70; Trailer composite 24 1st, 32 standard plus 4 tip up; Trailer 61 plus 9 tip up and 2 wheelchair spaces; Driving motor standard 70. The first class saloon is in the centre of the Trailer composite, which includes an office for the guard at the end adjacent to the other trailer.
• Number series: 450001 to 450100.
• Named units:
  450015 Desiro
  450042 Treloar College

A further 10 units are on order