British Rail Class 450

The British Rail Class 450 (4DES) third-rail DC EMU began service during 2003. They are a part of the Siemens Desiro modular train family. Used for outer suburban services, the Class 450 was built with standard and first class accommodation. The unit has a maximum speed of 100 mph (161 km/h).

British Rail Class 450 (4DES) Desiro
450111 at Basingstoke sunshine whole unit 40163328080.jpg
South Western Railway Class 450 No. 450111 at Basingstoke
SWR Class 450 Standard Class Interior.jpg
The interior of refurbished Standard Class aboard a SWR Class 450
In service5 October 2003 – present
ManufacturerSiemens Mobility
Built atKrefeld, Germany
Family nameDesiro
Entered service2003–2006
Number built127 trainsets
Number in service127 trainsets
Formation4 cars per trainset
Design code4-DES
Fleet numbers
  • 450001 – 450127
Capacity24 first class, 240 standard class per trainset
Operator(s)South Western Railway
Car body constructionAluminium
Car length20.4 m (66 ft 11 18 in)
Width2.796 m (9 ft 2 18 in)
DoorsPlug sliding 1/4 and 3/4 position
Articulated sectionsInter-unit and inter-vehicle flexible diaphragm
Maximum speed100 mph (161 km/h)
WeightTotal: 170 tonnes (167 long tons; 187 short tons)
Electric system(s)750 V DC third rail
Current collection methodContact shoe
Braking system(s)Air, regenerative
Track gauge1,435 mm (4 ft 8 12 in) standard gauge

The Siemens "Desiro UK" family also includes units of Classes 185, 350, 360, 380 and 444. These trains are the most numerous trains in South Western Railway's fleet, and also the most numerous units in the Desiro UK family.

In August 2017, the units transferred to South Western Railway, owned by FirstGroup and MTR Corporation.


South West Trains Siemens Class 450/0 Desiro EMUs No. 450075 and 450109 at Clapham Junction stabling sidings.

In April 2001, 785 vehicles were ordered by South West Trains in order to complete the replacement of its slam-door rolling stock, in accordance with its franchise commitment to do so by 2005, as the slam-door trains were coming to the end of their useful lives, and did not meet modern health and safety requirements. Introduction to service was delayed by the required power supply upgrades capable of powering the new trains, which feature air conditioning, a feature not present in the slam-door trains they replaced. In the December 2004 timetable change, the Class 450 Desiro began serving most intended routes, although introduction was delayed until June 2005 in some areas. The units are leased by Angel Trains to South West Trains.

Sixty-eight new vehicles were ordered by South West Trains as a replacement to the growth order which was diverted to form the similar Class 350 range of electric multiple units.


The entire Class 450 series consists of four car multiple units, semi permanently formed as DMSO(A)+TCO+TSO+DMSO(B).

Units numbered in the range 450001-110 consist of:

  • 63201-63300 and 63751-63760 – DMSO(A)
  • 64201-64300 and 66851-66860 – TCO
  • 68101-68200 and 66801-66810 – TSO
  • 63601-63700 and 63701-63710 – DMSO(B)

Units numbered in the range 450111-127 consist of:

  • 63901-63917 – DMSO(A)
  • 63921-63937 – TCO
  • 66901-66917 – TSO
  • 66921-66937 – DMSO(B)


South West Trains Class 450 No. 450112 at London Waterloo
The interior of First Class cabin from a Class 450/0

The Class 450 Desiro trains operate on certain London commuter rail routes, as well as outer suburban and regional services from London Waterloo, and local services outside of the London area. They are used on all SWR lines except the West of England line and the Eastleigh to Romsey Line. These include:

They can also be found on London commuter rail services usually operated by Class 455 units (to Woking, Guildford, Dorking, Chessington South, Hampton Court, Shepperton and the Kingston Loop Line), particularly in the peaks and on Sundays during periods of engineering work. These trains used to be seen in service between Wareham and Brockenhurst rail stations but now there are two trains an hour to London Waterloo from Weymouth, which are operated by SWR 444 units and an hourly slow train service from London Waterloo to Poole which is shared between Class 450s and Class 444s.

Class 450 Desiro trains are used on the Portsmouth Direct Line for London Waterloo to Portsmouth Harbour services in place of Class 444 Desiro units on some services. The decision to use Class 450 Desiros has been a cause for complaint from passengers specifically because of the 3+2 seating arrangement.[1]

The Class 450/2 and more ordersEdit

The interior of Standard Class accommodation aboard a Class 450

Originally, SWT’s order with Siemens was for 100 four-car sets (the current 450/0) and for 32 five-car sets, intended as Class 450/2, which would be for inner-suburban use. The Strategic Rail Authority, however, did not agree to the terms required, such as the lengthening of platforms and changes to railway infrastructure. As a result, the 32 five-car sets were cancelled, with the 160 vehicles redistributed; an extra 10 four-car sets were added to the SWT order, while the remaining 120 vehicles were then ordered as 30 four-car sets of the dual-voltage Class 350 for Silverlink and Central Trains.

Subsequently, SWT received further 17 four-car sets, bringing the total number of Class 450 units up to 127. These units were delivered in 2006, not long after the last of the first order was delivered. 450101 was damaged in Belgium and returned to Test- and Validationcenter Wegberg-Wildenrath to have repairs conducted by Siemens, therefore delaying its entry into the UK.

Class 450/5 modificationsEdit

In January 2008, 28 Class 450/0 sets were modified and re-numbered in the Class 450/5 series, for use on services between Waterloo and Windsor, the Hounslow Loop Line, as well as between Waterloo and Weybridge. They had their first class seating removed and replaced with 2+3 formation standard class seating and some other seats were removed to provide more standing capacity; extra handrails were also provided. The numbers modified are 450043 to 450070, which have become 450543 to 450570 respectively and displayed the letters HC (denoting 'High Capacity') above the unit number on the front of the sets. The modifications were carried out at the Bournemouth Traincare Depot.[2]

In anticipation of the Class 458/5 modifications for use on the Windsor Lines, the 450/5 sub class had the First Class reinstated, and they are now used generally across the SWR routes, however, these trains retain their 4505xx number as the standard seating configuration remains different. As they complete their latest interior refurbishment, during late 2019, they are being returned to their original numbers.

SWR Refresh (2018-19)Edit

South Western Railway (as part of their contract) have been carrying out a refurbishment programme on their Class 450 fleet. As part of this, every unit will be deep cleaned with carpets and seat covers replaced and every two seats in Standard Class will have a plug socket fitted. First Class will be reduced to 8 seats per set end (16 seats per set), and will feature new leather seats and tables with wireless charging facilities. As part of this work, Class 450/5s will also be similarly refurbished, and renumbered to their original numbers, so all Class 450s will once again share a common layout. [3]

The interior of the refurbished First Class cabin, showing the leather seats.

SWR Developments (2019-Present)Edit

During 2019, all of the High Capacity Class 450/5 units were formed back in to their original seating formations, with first class re-added as a result, as part of the refurbishment programme. As such, all of the units were renumbered back in to their original 450/0 numberings. The work took place at Eastleigh Works (Arlington Rail) and the last unit left Eastleigh early May, thus bringing an end to the 450/5 subclass.[4]

Accidents and incidentsEdit

  • On 6 November 2017, unit 450 025 was derailed near Wimbledon.[5] Four people were injured; over 300 passengers were evacuated from the train.[6] The accident was caused by track spread. Neither Network Rail nor London Underground had inspected the track for many years, due to a misunderstanding as to who was responsible for maintaining a 120-metre (130 yd) stretch of line.[7]

Fleet detailsEdit

Class Operator No. Year Built Carriages Unit nos.
450 South Western Railway 127 2002–06 4 450001–450127



  1. ^ "Commuter protest over rail seats". BBC News. 22 January 2007. Retrieved 29 January 2008. Commuters travelling between Portsmouth and London have set up a campaign group to try and change the new trains used on the railway line. A shake-up of rolling stock led to high density seating, designed for suburban journeys, being introduced on the line. Ian Johnston, of SWT, said: "It's about providing capacity on the lines of route where it is most needed. The dilemma we have is people either have to stand or we provide a seat, which may, in their opinion, be less comfortable than they were used to. The changes have provided 4,500 extra seats at peak times." Campaigners dispute this, saying that the Portsmouth Direct Line does not suffer from overcrowding on over 96% of its weekly services, and then only on the 25-minute section between Woking and Waterloo at peak times. Full details about the campaign are at
  2. ^ "High capacity Class 450 Desiro sets enter traffic". 24 January 2008. Retrieved 29 January 2008.
  3. ^ "SWR Refurbishment". Retrieved 29 November 2018.
  4. ^ "23rd December 2019 - Arlington Eastleigh Works". Retrieved 6 September 2020.
  5. ^ "South West Railways train derails near Wimbledon". BBC News Online. Retrieved 6 November 2017.
  6. ^ "Hundreds evacuated and four people injured after train derails near to Wimbledon". Independent Television News. Retrieved 6 November 2017.
  7. ^ "Derailment of a passenger train near Wimbledon, south-west London, 6 November 2017" (PDF). Rail Accident Investigation Branch. Retrieved 7 February 2018.