Pacer (British Rail)

Some Pacers were based on the Leyland National bus

The Pacer series were built with low construction and running costs in mind, and so all of the Pacer units use:[5][6]

• A lightweight modified bus body and other bus components, such as seating, with a reinforced driver's cab area to comply with crashworthiness standards.
• A long-wheelbase four-wheel freight-wagon-inspired underframe, rather than the conventional arrangement of two four-wheeled bogies. This arrangement has been criticised for rough-riding, and causing loud noise and excessive wear to the wheels and track on tight curves.

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.[7] 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.[8]

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.[8] While the more ambitious latter requirement would ultimately lead to the development of the British Rail Class 151 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.[8]

During this period, a number of prototypes were constructed to explore different designs and approaches for implementing the railbus concept. The initial prototype, known as LEV 1, was a joint project by the British Rail Research Division and Leyland Motors and used a bus body mounted on modified freight vehicle underframe (HSFV1). A subsequent test vehicle, a single two-car unit, designated as the Class 140, was constructed between 1979 and 1981.[9] The principal difference between the Class 140 and the preceding R3 concept was the incorporation of the underframe structure into the body above, thus making the latter a load-bearing structure.[8] Other changes included the strengthening of the cant rail area and the use of standard BR multiple unit ends, enabling compliance with full Union Internationale des Chemins de fer (UIC) end load specifications for multiple units.[8] Internally, a mixture of standard railway multiple unit seating and bus seating was installed. The resulting railbus was relatively lightweight, as had been desired by BR's concept.[8]

The Pacers had originally originally intended as a low-cost stopgap solution to the rolling stock shortage, with a maximum lifespan of 20 years.[5][10] A total of 165 Pacer trains (totalling 340 carriages) were built for BR. By 2015, the majority of these remained in operation with various private train operating companies, despite the type being in excess of 30 years old. Outside of the UK, Pacer demonstrator units toured various nations, including the U.S., Northern Ireland, Belgium, Sweden, Thailand, Malaysia and Indonesia, without producing significant sales. However ,Iran purchased redundant Class 141 units, for use on suburban lines around Tehran until 2005.[10]

The prototype Pacer Class 140

The Pacer series was the result of an experiment to assess the viability of using bus parts to create a diesel multiple unit. The two-car Class 140 was a prototype vehicle that was built in 1980 at British Rail Engineering Limited (BREL)'s Derby Litchurch Lane Works. This prototype was introduced with much fanfare during June 1981.[9] During its trial period, the Class 140 toured various lines across the UK. It later functioned as a demonstration unit for the incoming fleet based on the type, the Class 141.[9] By 1985, the unit was in use as a driver training vehicle.[9] From September 1986, the sole Class 140 was allocated to Neville Hill.[11]

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.[8] 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.[8] The original traction power train of the Class 140 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.[12] This propulsion arrangement was in part taken from the Leyland National bus. The controller for the automatic transmission was observed by BR engineers to the cause of numerous operating failures and other reliability issues; this was allegedly due to defective relay logic and poor earthing.[8]

A preserved Class 141 at the Colne Valley Railway. The resemblance to the bus is clear by the flat roof and windows.

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.[8] 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.[8] Accordingly, BR placed orders for two new models of the Pacer family with separate manufacturers, these being the Class 142 and Class 143 respectively.[8]

The prototype was joined by another 20 two-car units which formed the Class 141 fleet. The units were used mainly in Yorkshire, operating on predominantly suburban services. They had a capacity of 94 passengers per two-car set, and two Leyland TL11 engines gave a total of 410 bhp (310 kW), resulting in a top speed of 75 miles per hour (121 km/h). The Class 141s were built with standard Leyland National bodies, whose comparatively narrow width meant they could only be fitted with standard bus seating. The later Pacers had widened body panels to allow increased seating. Furthermore, in order to maximum cost savings, the manufacturers made use of road bus-standard electrical equipment, passenger fittings, and general cab layout wherever possible.[8]

During 1988, in response to reliability problems related to the electronics used, the entire class was briefly withdrawn and underwent a technical upgrade in 1988 at the Hunslet-Barclay works in Kilmarnock. The reliability issue was largely resolved via the replacement of the original relay-based controller of the transmission with an alternative that was microprocessor-based.[8] The units were permanently withdrawn from British Rail service in 1997. Many Class 14s were sold to Islamic Republic of Iran Railways.[10]

An Arriva Trains Northern Class 142 Pacer at Leeds

The next and largest Pacer class was the Class 142. As BR was considering ordering more railbuses, it was decided that, instead of placing these follow-on orders for further Class 141 vehicles, it would be more desirable to procure improved derivatives of the Class 141.[8] Accordingly, BR placed orders for two new models of the Pacer family with separate manufacturers, these being the Class 142 and Class 143 respectively.[8]

The Class 142 again was built by Leyland and BREL, in 1985. The body was based on a Leyland National bus, built at Workington in Cumbria. Many fixtures and fittings of the Leyland National could be found on the units. The new class had a greater capacity of 120 passengers per two-car set and the same engines were used. The first sets were used initially on Devon and Cornwall branch lines and on commuter services in the north west. The units from Cornwall were eventually moved to Liverpool and the north east, and the Class 142s became a common sight on services across the north of England.

The Class 142s received substantial upgrades during the early 1990s, which included the installation of more powerful Cummins engines, which gave a total power output of 460 bhp (340 kW) per two-car set. A number of units were then modified for use on the Merseyside PTE City Line on Merseyrail in the Liverpool region, which included dot-matrix route indicators, improved seating and Merseyrail PTE paintwork.

The Class 142s moved into the control of Arriva Trains Northern and First North Western at privatisation, and subsequently passed on to Northern Rail, Arriva Rail North, Northern Trains, Arriva Trains Wales and Transport for Wales. Eight Northern Rail units were temporarily withdrawn from service, replaced by a cascading of British Rail Class 158s.[13] First Great Western received 12 units on loan from Northern Rail from December 2007 to November 2011 (five units were returned to Northern in December 2008) to cover for refurbishment of its fleet and to allow most of its Class 158 fleet to be rebuilt as three-car sets.

Three coach Class 144 at York

Around the same time of the Class 142 development, a Pacer railbus was being developed by Kilmarnock based Hunslet-Barclay. The units used a Walter Alexander bus body. The units were given the number Class 143 and entered service in 1985. Again with two 205 bhp engines giving a total output of 410 bhp (310 kW) and a top speed of 75 mph (121 km/h), the class originally had a capacity of 122 passengers. The class was used in the North East before being transferred to Wales and the South West, and were moved over to Valley Lines and Wales & West control during privatisation. They then passed on to Arriva Trains Wales, Wessex Trains, First Great Western and Transport for Wales. The interiors were completely changed in 2000, when the Valley Lines service was introduced, with full back, coach-type seating installed throughout, along with improved fittings. This reduced seating capacity to 106 seats per set.

It was followed by the similar Class 144, comprising a Walter Alexander body on BREL underframe, which was introduced in 1987. The most substantial design change was the replacement of the Leyland-built engine with a more powerful Cummins LTA10-R counterpart,[14][15] as well as the original mechanical transmission being substituted for a Voith hydraulic unit.[16][17] A Class 144 unit was formed of either a two-car set with 122 seats or a three-car set with a total capacity of 195 passengers and 690 bhp (510 kW), though still limited to 75 mph (121 km/h). The units were used in the North East, passing to Northern Spirit at privatisation, then to Arriva Trains Northern, Northern Rail, Arriva Rail North and now Northern Trains.

Pacers will be primarily replaced by upgraded 150s (interior pictured right/below) from other lines following the introduction of the Class 195. The 150 units will offer more capacity and in many cases operate as four-carriage services.

As of 2020, the oldest Pacers on the national network were appoaching 35 years old. All were planned to be withdrawn and scrapped by December 2019 as they do not comply with Rail Vehicle Accessibility Regulations.

Several Pacers have been preserved for further use on heritage railways. The National Railway Museum has preserved 142001.[30]

In May 2019, the government called for a public consultation on re-using the trains after withdrawal from service; suggestions have included re-using them as public spaces, such as village halls or cafes.[31]

Wikimedia Commons has media related to British Rail Pacers.

• Reeve, Tom (24 September – 7 October 1997). "What future for humble 'Pacer'?". Rail. No. 314. EMAP Apex Publications. pp. 34–39. ISSN 0953-4563. OCLC 49953699.