British Rail Class 143

British Rail Class 143 Pacer

A Great Western Railway Class 143 Pacer No. 143617 at Exeter TMD, opposite Exeter St. Davids Station. This was the first one to be refurbished for Great Western Railway.

The interior of a First Great Western refurbished Class 143
In service 1985 - present
Manufacturer Hunslet-Barclay and Walter Alexander
Order number
  • 31005 (DMS)
  • 31006 (DMSL)[1]
Family name Pacer
Replaced First generation DMUs
Constructed 1985-1986[1]
Entered service 1985
Refurbishment 1990s/2001-2002[2]
Number built 25 trainsets
Number in service 23 trainsets
Number scrapped 2 trainsets (both due to fire)
  • 2 cars per trainset
  • DMS+DMSL[2]
Fleet numbers
  • 143001-143025 (sets, as built)
  • 55642-55666 (DMS)
  • 55667-55691 (DMSL)[4]
  • 62S (DMS)
  • 60S (DMSL)[1]
Line(s) served
Car body construction Steel[2] underframe. Aluminium alloy body and roof.
Car length 15.546 m (51 ft 0 in)[3]
Width 2.695 m (8 ft 10.1 in)[3]
Height 3.515 m (11 ft 6.4 in)[3]
Doors Twin leaf pivot[2]
Articulated sections 2
Wheelbase 9.000 m (29 ft 6.3 in)[3]
Maximum speed 75 mph (121 km/h)
  • 24 t (24 long tons; 26 short tons) (DMS)
  • 24.5 t (24.1 long tons; 27.0 short tons) (DMSL)[1]
Prime mover(s)
  • 1 × Cummins LTA10-R[7] 230 hp (170 kW) (per car)[2]
  • (Originally fitted with Leyland TL11[1] 6-cylinder 11.1-litre)
Engine type 10-litre[7] diesel
Cylinder count 6
Power output
  • Cummins: 225 hp (168 kW) at 2100 rpm[7]
  • Leyland: 205 hp (153 kW)[1] at 1950 rpm
Train heating Engine waste heat, ducted warm air[3]
Bogies None, Ax1[3] fixed axle
Braking system(s) Air[3]
Safety system(s)
Coupling system BSI[8]
Multiple working Classes 14x, 15x and 170[2]
Headlight type Fluorescent[3]
Track gauge 1,435 mm (4 ft 8 12 in) standard gauge

The British Rail Class 143 is a diesel multiple unit, part of the Pacer family of trains introduced between 1985 and 1986. They originally worked in the North-East of England but were later transferred to Wales and South-West England.[9]

The Rail Vehicle Accessibility (Interoperable Rail System) Regulations 2008[10] require that all public passenger trains must be accessible by 1 January 2020. No Pacer trains currently meet this requirement. Porterbrook has proposed an extensive refurbishment of the Class 143 and 144 units in an attempt to meet this requirement although this would significantly reduce the number of seats.[11] Arriva Rail North must not operate any Pacer trains after 31 December 2019. They are required to order at least 120 new self-powered vehicles and are permitted to take on Sprinter and Turbostar units released by other franchises.[12] The Long Term Passenger Rolling Stock Strategy for the Rail Industry indicates up to 500 non-electric carriages will need to be built in the short term.[13]

The units are currently used on short distance services around Cardiff and Exeter. Previously they were common on services in the Bristol area.


Unlike most other stock on the UK network, Class 143s (in common with other Pacers) lack bogies, instead having single axles at each end of the vehicle (Red Boxes).

At around the same time as the British Rail Class 142 was in development, a Pacer railbus was being developed by Kilmarnock-based Hunslet-Barclay. The units used a Walter Alexander bus body and entered service in 1985. Again with 2 × 205 bhp (153 kW) engines giving a total output of 410 bhp (306 kW) and a top speed of 75 mph (121 km/h), the class 143s originally had a capacity of 122 passengers per 2-coach unit.

As with all Pacer units, the 2-axle non-articulated wheel arrangement has given rise to problems with wheel noise on low-radius curves and poor ride quality in general. The interiors were completely changed in 2000, with bespoke Chapman high-back seating installed throughout, along with improved fittings, replacing 2+3 bus-style low-back seating; this reduced seating capacity to 106 seats per set.


North East

The class was based at Heaton depot (Newcastle) from new, for use in the North East of England on services based around Newcastle, Darlington and Middlesbrough. Of the original twenty-five units built, 143001-019 were supplied in Provincial railbus-style two-tone blue and white stripe livery, and 143020-025 were supplied in Tyne & Wear PTE yellow+white livery.

As with the similar Class 142 units, problems soon emerged with the SCG mechanical transmission, resulting in poor availability, and frequent loco-hauled substitutions by Classes 47 / 31 on local services to Middlesbrough / Carlisle, especially in 1987, continuing to a lesser extent in 1988 and 1989, as the units were progressively fitted with the more robust Voith hydraulic transmissions. Improved availability of the units - coupled with the influx of several former West Country Class 142 units - enabled the Class 101s to be eliminated from Heaton depot in 1989... meanwhile the loco-hauled substitutions also dwindled to typically one set diagram per day, finally ending altogether in Summer 1990, by which time the Pacers had generally settled down to give more acceptable reliability.

During the problems, a total of four original formations were split, and reformed to make operational DMS-DMS(L) sets, in a bid to alleviate the acute DMU shortage in the region. First to be split were 143002 and 143010, and cars 55643+55676 actually carried unit no. 143026 for a time in 1988. However, the pair was later renumbered 143010. The other cars 55651+55668 appeared later in 1988, with 55651 having a large white number 2 - meant for coach sides - crudely placed across the black 10 of its original unit number, only rectified upon later renumbering to 143602...

In 1989, Heaton depot implemented a unit renumbering scheme, whereby those with original SCG mechanical transmission would be renumbered 1433XX, and those that had undergone conversion to Voith hydraulic transmission would be renumbered 1436XX. By this time, many units had already received Voith transmission, so were renumbered directly from 1430XX to 1436XX. Only the T&WPTE-sponsored units - which received Voith transmission later on - actually carried the 1433XX series, renumbered to 1436XX when they were eventually converted.

143003 had spent a lengthy spell out of action with fire damage, then in Summer 1989, car 55644 from it was paired with 55683 (ex-143617), and both given the unit number 143617. The other cars 55658+55669 re-appeared later that Summer, both carrying unit number 143603. These reformations were never reversed to original formations, thus 143602, 143603, 143610 and 143617 remained mis-formed ever since.

143025 did carry the name of 'River Tyne' for some time when it was based in the North East


From 1991/92, the units started to be transferred to Cardiff Canton depot for operations in South Wales, and moved over to Wales & West control during privatisation. It then passed on to Wessex Trains, which became part of the First Great Western franchise. Arriva Trains Wales uses its Class 143 units, alongside its Class 142 units, on commuter lines around Cardiff to places such as Rhymney, Aberdare, Barry Island and Bridgend.

It operates 15 sets. Arriva's fleet was repainted in turquoise and cream Arriva Trains Wales livery. 143609 has been named 'Sir Tom Jones' in honour of the Welsh singer.[6]

Arriva Trains Wales began a minor interior refresh of its Class 142 and 143 pacer fleets in Autumn 2009. The seats are being retrimmed into the Arriva moquette. Additionally on the exterior of the Class 142 and class 143 Pacers, LED head and rear marker lights and LED door obstruction marker lights are being installed.

South-West England

Wessex Trains used their fleet primarily on commuter services around Bristol, although towards the end of the franchises they were increasingly on longer distance Cardiff Central to Taunton services. They were occasionally used on rural branch lines but this was generally avoided where possible due to problems with wheel wear and the noise on sharp corners.

First Great Western inherited the seven Wessex Trains units when the franchises were merged in April 2006. An eighth set used by Wessex Trains (143613) caught fire near Nailsea and Backwell in October 2004 and was scrapped.

In Autumn 2008, the Class 143s began a further refurbishment program at Eastleigh works; the interior improvements include:

Since December 2008 the Class 143s are based at Exeter TMD alongside seven similar Class 142s (although the Class 142s were sent to Northern in 2011 when replaced by surplus Class 150s from London Midland). They are now allocated to the following services:

Liveries and interiors


On 17 October 2004, Wessex Trains unit 143613, forming the 20:06 2W63 service from Bristol Temple Meads to Weston-super-Mare with 143621, caught fire between the site of the former Flax Bourton railway station and Nailsea and Backwell. Fire services took two hours to get the blaze under control. Of the 23 passengers and crew three were treated on-site for the effects of smoke inhalation. One carriage was completely burnt out, and the other was badly damaged, causing the train to be written off.[14] The line through Nailsea was closed until 03:30 the following morning, when the train was hauled to St Philips Marsh Traction and Rolling Stock Maintenance Depot for examination.[15] The unit was later taken to Crewe Works where it was stored,[15][16] then later to Cardiff Canton TMD where it was scrapped.[17] The Rail Safety and Standards Board issued a report into the incident, concluding that the fire was caused by electrical arcing between the live starter motor cable (which had damaged insulation) and the unit's underframe, causing accumulated oily residues to ignite.[18]

Fleet details

Class Operator No. Built Year Built Cars per Set Unit nos. Notes
Class 143 Arriva Trains Wales 15 1985-1986 2 143601/602/604-610/614/616/622-625 143615 withdrawn after fire damage (2005)
Great Western Railway 8 143603/611/612/617-621 143613 withdrawn after a fire (2004)

Named units

One unit has received a name:[19]


  1. 1 2 3 4 5 6 7 Fox 1987, p. 41
  2. 1 2 3 4 5 6 "Class 143". The Railway Centre. Archived from the original on 9 March 2005.
  3. 1 2 3 4 5 6 7 8 9 10 11 Vehicle Diagram Book No. 220 for Diesel Multiple Unit Trains (Railcars) (PDF). Barrowmore MRG. Derby: British Railways Board. 1982. DP236, DP237.
  4. 1 2 Fox 1987, pp. 41-42
  5. 1 2 Fox & Hughes 1994, p. 26
  6. 1 2 "Fleet lists: Class 143". Archived from the original on 17 January 2007.
  7. 1 2 3 Pritchard & Fox 2009, p. 14
  8. "System Data for Mechanical and Electrical Coupling of Rail Vehicles". Rail Safety and Standards Board. Archived from the original on 5 July 2008. Retrieved 5 January 2009.
  9. "Class 143". The Railway Centre. Archived from the original on 8 March 2005.
  10. Rail Vehicle Accessibility (Interoperable Rail System) Regulations 2008
  12. "Northern: Invitation to Tender" (PDF). Department for Transport. 27 February 2015. Retrieved 20 February 2016.
  13. "More rolling stock needed as passenger growth rises again". Railnews. 9 March 2015. Retrieved 20 February 2016.
  14. "Commuters escape from train blaze". BBC News. 19 October 2004. Retrieved 20 April 2012.
  15. 1 2 "December 2004 magazine". Cardiff & Avonside Railway Society. December 2004. Retrieved 27 April 2012. A serious incident just short of Nailsea & Backwell station (alongside the common), saw the 2W63 20.06 Temple Meads-Weston-super-Mare local Wessex Trains service, formed with 143613 + 143621, stopped and evacuated due to a fire which gutted coach 55654 and smoke damaged 55679 (both from set 143613). Fire services took two hours to get the blaze under control, the flames reaching around 20 feet in height, but there were no serious injuries, three persons being treated for smoke inhalation of the 23 passengers and crew travelling on the service. The mainline was closed until 03.30 the following day, the units being dragged back to Bristol and store at St.Phillips Marsh depot for examination. The fire was thought to have started due to a mechanical fault. 19/10 143613 was taken to St Phillips Marsh for an investigation into the fire. The main frame of 55654 was badly buckled and it is beyond repair. The unit was taken by road to Crewe Works later in the week.
  16. "November 2005". Cardiff & Avonside Railway Society. November 2005. Retrieved 17 June 2012. Stored: 143613/615 - ZC [Crewe Works]
  17. "September 2006". Cardiff & Avonside Railway Society. September 2006. Retrieved 17 June 2012. Disposals: Pullman : 143613 @CF [Cardiff Canton]
  18. "August 2005 section: "Miscellaneous"". Cardiff & Avonside Railway Society. August 2005. Retrieved 27 April 2012.
  19. "DMU FORMATIONS". AbRail. Retrieved 27 March 2015.


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