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British Rail Class 143 Pacer
Great Western Railway Class 143 at Dawlish in 2018
Great Western Railway refurbished saloon
In service	1985–2021
Manufacturer	Hunslet-Barclay Walter Alexander Coachbuilders
Order no.	31005 (DMS vehicles) 31006 (DMSL vehicles)
Family name	Pacer
Replaced	BR First-Generation DMUs
Constructed	1985–1986
Refurbished	1990s 2001–2002 2015–2016
Number built	25
Number preserved	13
Number scrapped	12
Formation	2 cars per unit: DMS-DMSL
Diagram	DMS vehicles: DP236 DMSL vehicles: DP237
Fleet numbers	As built: 143001–143025 Later: 143601–143625
Capacity	In 4-abreast config.: 104 seats In 5-abreast config.: 122 seats
Specifications
Car body construction	Steel underframe, aluminium alloy body and roof
Car length	15.546 m (51 ft 0 in) (over couplers)
Width	2.695 m (8 ft 10.1 in)
Height	3.515 m (11 ft 6.4 in)
Doors	Double-leaf folding (three per side)
Wheelbase	9.000 m (29 ft 6.3 in)
Maximum speed	75 mph (121 km/h)
Weight	DMS vehs.: 24.0 t (23.6 long tons; 26.5 short tons) DMSL vehs.: 24.5 t (24.1 long tons; 27.0 short tons)
Axle load	Route Availability 1
Prime mover(s)	As built: 2 × Leyland TL11 After upgrade: 2 × Cummins LTA10-R (one per vehicle)
Engine type	Inline-6 4-stroke turbo-diesel
Displacement	Leyland: 11.1 L (680 cu in) Cummins: 10.0 L (610 cu in) (per engine)
Power output	Leyland: 149 kW (200 hp) Cummins: 168 kW (225 hp) (per engine)
Transmission	As built: SCG RRE5 (4-sp. epicyclic) After upgrade: Voith T 211 r (hydrokinetic)
Minimum turning radius	70 m (230 ft)
Braking system(s)	Electro-pneumatic (tread)
Safety system(s)	AWS TPWS
Coupling system	BSI
Multiple working	Within class, and with Classes 14x, 15x, and 170
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge
Notes/references
Specifications as at March 1985 except where otherwise noted.

The British Rail Class 143 are diesel multiple unit passenger trains, part of the Pacer family of passenger trains introduced between 1985 and 1986.

During the 1980s, British Rail (BR) was interested in replacing its first-generation diesel multiple units, particularly in the use of railbuses to service its lightly used branch lines. It was decided to develop such a vehicle with a high level of commonality with the widely used Leyland National bus, leading to its modular design serving as the basis for the design. Several single- and two-car prototypes were constructed and evaluated, leading to an initial production batch by British Leyland, designated Class 141 units. BR, seeking to procure improved derivatives of the Class 141, placed an order with the manufacturers Hunslet-Barclay and Walter Alexander to construct its own variant, the Class 143.

Entering operational service during the mid-1980s, the Class 143 embodied several advances over the original model in terms of ride quality and reliability. During its operating lives, the type operated various passenger services across the United Kingdom; initially operated in the North-East of England, all units were subsequently transferred to other regions, including Wales and South-West England.

Due to their non-compliance with the Rail Vehicle Accessibility (Interoperable Rail System) Regulations 2008, the Pacer family began to be withdrawn during the late 2010s ahead of the 1 January 2020 deadline. Some fleets were given dispensation to operate until 31 December 2020. While modifications for compliance were proposed by rolling-stock companies, no train operator took up the option. Great Western Railway retired its Class 143 fleet in December 2020, while Transport for Wales was granted an extension and ran its trains until 29 May 2021.

Background

By the beginning of the 1980s, British Rail (BR) operated a large fleet of first generation DMUs, which had been constructed in prior decades to various designs. While formulating its long-term strategy for this sector of its operations, British Rail planners recognised that there would be considerable costs incurred by undertaking refurbishment programmes necessary for the continued use of these aging multiple units, particularly due to the necessity of handling and removing hazardous materials such as asbestos. In light of the high costs involved in retention, planners examined the prospects for the development and introduction of a new generation of DMUs to succeed the first generation.

In the concept stage, two separate approaches were devised, one involving a so-called railbus that prioritised the minimisation of both initial (procurement) and ongoing (maintenance & operational) costs, while the second was a more substantial DMU that could deliver superior performance than the existing fleet, particularly when it came to long-distance services. While the more ambitious latter requirement would ultimately lead to the development of the British Rail Class 150 and the wider Sprinter family of DMUs, BR officials recognised that a cheaper unit was desirable for service on the smaller branch lines that would not be unduly impacted by lower performance specs or a high density configuration. As such, work to progress both approaches was undertaken by BR's research department during the early 1980s.

During this period, a number of prototypes were constructed to explore different designs and approaches for implementing the railbus concept. One such vehicle was a single two-car unit, designated as the Class 140, that was constructed between 1979 and 1981. This prototype was introduced with much fanfare during June 1981. Initial testing with the Class 140 uncovered several issues, such as difficulty detecting the type via track circuits, this was reliably resolved by swapping the material of the brake blocks from a composite to iron. Two less easily addressable drawbacks were the high level of noise generated during transit, particularly on older jointed rails, which was a consequence of the railbus's direct connection between the underframe and suspension with the body that transmitted impact forces across the body. It was also observed that the inclusion of strengthening members in the mass-produced bus body added significantly to the overall production cost, which eliminated much of the cost advantage that was the primarily goal of the type.

The Class 140 was viewed to be an overall success, and thus BR issued an order for an initial production model, designated Class 141, to British Leyland during 1984 with production commencing thereafter. During its early years of service, the Class 141 experienced numerous issues, particularly with the transmission and ride quality; work undertaken at BR's direct resulted in the quick development of numerous improvements to at least partially address these shortcomings. When it came to ordering more railbuses, however, it was decided that instead of placing these follow-on orders for further Class 141, it would be more desirable to procure improved derivatives of the Class 141. Accordingly, BR placed orders for two new models of the Pacer family, these being the Class 142 and Class 143 respectively.

Design

The Class 143 shared a high degree of similarity to the design of the Class 141. However, one major area of change is that both the Class 142 and Class 143 featured a noticeably wider body, instead of adhering to the width of the standard bus as per the Class 141; specifically, the width was expanded to the maximum amount permissible to remain within the loading gauge. This resulting in an increased internal area to accommodate passengers within, enabling a three-by-two seating arrangement to be installed for a total capacity of 121 seats. The increased seating was particularly useful as, in addition to their use on rural feeder services, the Class 143's use on short range urban services had been foreseen by BR planners.

Both the bodies and underframes were designed for interchangeability, as had been specified by BR. To achieve this, they were manufactured upon jigs. They had been designed so that the entire body could be replaced during a mid-life refurbishment/reconstruction, and that the replacement body would not be limited to the exact same dimensions either. The underframe area, in addition to its structural role, accommodated all of the propulsion apparatus along with the majority of electrical gear. As a cost-saving measure, the manufacturers were directly to make use of road bus-standard equipment in several areas, including passenger fittings and the general cab layout, along with other areas wherever possible. Unlike the Class 141, which featured automotive-standard wiring for the traction equipment with resulting poor performance, railway-grade wiring for the traction and braking circuits was mandated by BR for both the Class 142 and Class 143 to yield greater reliability.

As originally built, the traction arrangement of the Class 143 consisted of a Leyland TL11 200 HP engine, a Self-Changing Gears mechanical automatic gearbox and a Gmeinder final drive unit on each car driving only a single axle. This propulsion arrangement was in part taken from the Leyland National bus, as well as shared with the earlier Class 141. Unlike the Class 141, a microprocessor-based controller for the automatic transmission was used from the outset, allowing the reliability issues posed by defective relay logic and poor earthing present on the predecessor to be entirely avoided. Another improvement was the installation of auto-couplers and auto-connectors that enabled the Class 143 to work in multiple with the Class 150 Sprinter DMUs.

Both axles (one driving per coach at the inner end) were fitted directly to the chassis rather than being mounted on bogies, unlike traditional DMUs. This uncommon arrangement has been attributed with resulting in the Class 141 units possessing a relatively rough ride, especially when traversing jointed track or points. Their combatively poor ride quality has been said to be a major factor in the type's general unpopularity amongst passengers. As a positive result from BR's experiences with the Class 141, the Class 143 featured an improved suspension arrangement to enhance passenger comfort, this consisted of a wider spring base and double dampers being installed, features that had been deemed necessary by BR to provide sufficient levels of performance, and had been retrofitted onto all of the older Class 141s as well.

Operations

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During their early years, the Class 143s originally worked in the North-East of England. Subsequently, the entire fleet was transferred to Wales and South-West England.

The Rail Vehicle Accessibility (Interoperable Rail System) Regulations 2008 and the subsequent Persons of Reduced Mobility - Technical Specification for Interoperability (PRM-TSI) require that all public passenger trains must be accessible by 1 January 2020. As originally delivered, the Class 143 does not meet this requirement and had to be withdrawn without modifications to become compliant. During the 2010s, the rolling-stock leasing company Porterbrook proposed an extensive refurbishment of both the Class 143 and 144 units with the purpose of satisfying the diverse needs of this requirement; it was noted that the envisioned modifications would necessitate a significant reduction in the number of seats available.

Great Western Railway (GWR) was one such operator of the Class 143. Its units were mainly used on short-distance services around Exeter, but had previously been common on various services in the Bristol area as well. At one point, as part of the franchise's plans to modernise its fleet, GWR planned to withdraw its remaining eight units by December 2019 via a cascade programme that would see the type being entirely replaced with Class 150s. On 11 December 2019, the Department for Transport issued a dispensation, allowing GWR to continue to operate its Class 143 fleet up until 31 December 2020. Their fleet was withdrawn in December 2020.

Transport for Wales was granted an extension until May 2021, due to delays with the introduction of Class 769s and their last trains of the class ran on 29 May 2021. The last mainline passenger service with a Pacer unit in its formation was the 22:02 Rhymney to Cardiff Central worked by 143601 coupled to a 150/2 unit, this train brought an end to Pacer operation after over 35 years. Thereafter, the use of Pacer trains is confined to heritage lines.

Incidents

On 17 October 2004, Wessex Trains unit 143613, forming a 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. The line through Nailsea was closed until 03:30 the following morning, when the train was hauled to St Philip's Marsh depot for examination. The unit was later taken to Crewe Works where it was stored, then later to Cardiff Canton TMD where it was scrapped. 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.

On 16 January 2020, 143603 had several windows smashed in by waves and sea debris while running along the sea wall at Dawlish during stormy weather, causing minor injuries to one passenger.

Fleet details

Vehicle number ranges were as follows:

• DMS: 55642–55666
• DMSL: 55667–55691

Named units

Some units received names:

• 143605 Crimestoppers (scrapped)
• 143606 River Wear
• 143609 Sir Tom Jones (scrapped)
• 143617 Berwick's Swan
• 143618 Mute Swan
• 143619 Whooper Swan
• 143625 Valleys Kids

Preservation

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. Find sources: "British Rail Class 143" – news · newspapers · books · scholar · JSTOR (December 2022) (Learn how and when to remove this message)

Operational

Non-railway use

Alongside the operational preserved Class 143s, some have been acquired for non-operational use at heritage railways or for non-railway use.

Liveries

• BR Regional Railways blue (Carlisle, undated)
• BR Regional Railways sector livery (Seaham, 1991)
• Tyne & Wear PTE livery with 'TW Pacer' branding (Seaham, 1991)
• Wessex Trains 'Visit Bristol' (Bristol Temple Meads, 2005)
• Wales and Borders 'Valley Lines' with later Arriva branding (Gloucester, 2005)
• Arriva Trains Wales (Cardiff Central, 2009)
• First Great Western (Bristol Temple Meads, 2008)
• First Great Western (Bristol Temple Meads, 2009)
• Arriva Trains Wales 'Executive' (Cardiff Central, 2016)
• Great Western Railway (Exeter, 2017)

Interiors

• Arriva Trains Wales Cab
• Wessex Trains
• Wales & West 'Valley Lines'
• Arriva Trains Wales
• First Great Western
• Great Western Railway

References

Citations

1. ^ Fox, Peter (1987). British Railways Pocket Book No. 2: Multiple Units (Summer–Autumn 1987 ed.). Sheffield: Platform 5 Publishing. pp. 41–42. ISBN 0906579740. OCLC 613347580.
2. "Class 143". The Railway Centre. Archived from the original on 9 March 2005.{{cite web}}: CS1 maint: unfit URL (link)
3. ^ Class 143 & 144 Diesel Multiple Units (PDF) (1A ed.). Derby: Porterbrook Leasing Company. September 2012. Archived from the original (PDF) on 5 January 2016. Retrieved 29 December 2022.
4. ^ Pritchard, R.N.; Fox, Peter (2009). British Railways Pocket Book No. 3: Diesel Multiple Units 2010. Sheffield: Platform 5 Publishing. p. 14. ISBN 978-1-902336-75-6. OCLC 614300319.
5. ^ Leyland Titan Technical Data (PDF). Southall: British Leyland UK. June 1978. Lit. No. 1683. Archived (PDF) from the original on 31 January 2022. Retrieved 21 December 2022.
6. ^ Engine Performance Curve LTA10-G2. Columbus, Indiana: Cummins Engine Company. 14 April 1997. FR-2254. Archived from the original (PDF) on 22 December 2022. Retrieved 22 December 2022.
7. ^ Shore, A. G. L. (1987). "British Rail Diesel Multiple Unit Replacement Programme". Proceedings of the Institution of Mechanical Engineers, Part D: Transport Engineering. 201 (2): 115–122. CiteSeerX 10.1.1.1008.3291. doi:10.1243/PIME_PROC_1987_201_165_02. ISSN 0265-1904. S2CID 109194039.
8. Fox, Peter; Hughes, Barry (1994). British Railways Pocket Book No. 3: DMUs & Channel Tunnel Stock (7th ed.). Sheffield: Platform 5 Publishing. p. 26. ISBN 9781872524597.
9. Vehicle Diagram Book No. 220 for Diesel Multiple Unit Trains (Railcars) (PDF). Derby: British Railways Board. 1982. DP236 & DP237 (in work pp. 67–70). Archived from the original (PDF) on 21 January 2015. Retrieved 19 February 2016 – via Barrowmore MRG.
10. Thomas, David St John; Whitehouse, Patrick (1990). BR in the Eighties. Newton Abbot: David & Charles. ISBN 978-0-7153-9854-8. OL 11253354M. Wikidata Q112224535.
11. ^ Smith, R.I. (2002). Class 140: The Past, The Present, The Future. Keith & Dufftown Railway Association. pp. 3, 7. ISBN 0901845213.
12. "Class 143". The Railway Centre. Archived from the original on 8 March 2005.{{cite web}}: CS1 maint: unfit URL (link)
13. "The Rail Vehicle Accessibility (Interoperable Rail System) Regulations 2008". legislation.gov.uk.
14. "14x Brochure" (PDF). Porterbrook. Archived from the original (PDF) on 11 March 2014. Retrieved 11 March 2014.
15. "Modernising the Great Western railway" (PDF). National Audit Office. 2016. p. 49.
16. Wilkinson, Peter (6 June 2013). "The Railways (Interoperability) Regulations 2011 – Great Western Railway Class 143 - 2020 accessibility deadline" (PDF). Gov.UK. Department for Transport. Retrieved 31 December 2020.
17. "2+3 HSTs help oust GWR Pacers". Modern Railways. January 2021. p. 103.
18. "The Railways (Interoperability) Regulations 2011 – Transport for Wales Rail Services Class 143s - 2020 accessibility deadline" (PDF). Gov.UK. Department for Transport. 10 December 2020. Archived from the original (PDF) on 28 December 2020. Retrieved 31 December 2020.
19. "Last departure for Welsh Pacers". Rail News. 1 June 2021. Retrieved 1 June 2021.
20. "Commuters escape from train blaze". BBC News. 19 October 2004. Retrieved 20 April 2012.
21. ^ "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.
22. "November 2005". Cardiff & Avonside Railway Society. November 2005. Retrieved 17 June 2012. Stored: 143613/615 - ZC
23. "September 2006". Cardiff & Avonside Railway Society. September 2006. Retrieved 17 June 2012. Disposals: Pullman : 143613 @CF
24. "August 2005 section: "Miscellaneous"". Cardiff & Avonside Railway Society. August 2005. Retrieved 27 April 2012.
25. "Passenger hurt when wave smashes Great Western Railway train windows". BBC News. 16 January 2020. Retrieved 16 January 2020.
26. ^ Russell, David (January 2023). "Last 'Pacer' is disposed of, though many 'nodding donkeys' survive". Units. Rail Express. No. 320. p. 26.
27. "The Class 143". Modern Locomotives Illustrated. No. 196. Stamford: Key Publishing. August 2012. pp. 62–71.
28. "143603 - 55658 & 55669 Class 143 Driving Motor Second & Driving Motor Second Lavatory". The Railcar Association. 7 June 2021. Retrieved 12 June 2021.
29. "BR 55653 Class 143 Barclay/Alexander 4-wheel 'Pacer' DMS built 1985". Railway Heritage Register Partnership. Retrieved 4 June 2021.
30. "143612 - 55653 & 55678 - Class 143 Driving Motor Second & Driving Motor Second Lavatory". The Railcar Association. 1 May 2021. Retrieved 12 June 2021.
31. "Ex-GWR Class 143 arrives at Torrington Station". Great Torrington: Tarka Valley Railway. 16 November 2022.
32. "143617 Named After Founder Member and Chairman". Tarka Valley Railway.
33. Smith, Roger (30 May 2022). "GWR Class 143 to join Plym Valley Railway". RailAdvent. Retrieved 31 May 2022.
34. Harris, Nigel, ed. (12 July 2023). "Welsh Pacer on Wensleydale duty". Rail Magazine. No. 987. Peterborough: Bauer Consumer Media. p. 9. ISSN 0953-4563.
35. "Facebook". www.facebook.com. Retrieved 5 September 2024.

Further reading

• Marsden, Colin J. (2011). Traction Recognition (2nd ed.). Ian Allan. pp. 106–107. ISBN 9780711034945. OCLC 751525080.

• British Rail diesel multiple units
• Train-related introductions in 1985