|In service||1984–present (production units)|
|Number built||165 sets|
|Number in service||45 sets (National Rail)|
|Number scrapped||37 sets (142/143/144)|
|Track gauge||4 ft 8 1⁄2 in (1,435 mm) standard gauge|
Pacer is the operational name of the British Rail Classes 140, 141, 142, 143 and 144 diesel multiple unit railbuses, built between 1980 and 1987. The railbuses were intended as a short-term solution to a shortage of rolling stock, with a lifespan of no more than 20 years.
All Pacer trains were scheduled to be retired by the end of 2019. The Rail Vehicle Accessibility Regulations require that all public passenger trains must be accessible to disabled people by 2020. Only one Pacer (the modernised 144e) currently meets this requirement, and the remainder were therefore planned to be withdrawn by that date. Furthermore, a decision in 2015 by the Transport Secretary required that such railbuses be removed from service by 2020 for the then-new Northern franchise, stating that the "continued use of these uncomfortable and low-quality vehicles is not compatible with our vision for economic growth and prosperity in the north".
As of 30 August 2020[update], 45 units of classes 142, 143 and 144, which were upgraded in the 1990s with more reliable mechanical parts followed by the older standard of wheelchair access, are still in service with three National Rail operators: Northern Trains, Great Western Railway and Transport for Wales. All of those operators intended to retire their Pacer trains (a 140-strong fleet before their withdrawal) by the end of 2019, in line with the statutory instrument to improve accessibility on trains. However, with replacement rolling stock delayed, all three of these operators are continuing to operate their remaining units in 2020, under dispensation from law.
- 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.
At the beginning of the 1980s British Rail (BR) needed to produce new trains to replace its ageing fleets of first generation diesel multiple units (DMUs) which had been built between the mid-1950s and early-1960s. These first-generation units had helped replace steam and had, when introduced, proved popular with the public. At the time BR was under severe financial pressure from the government and lacked the money to replace all of them with units of similar quality. BR developed two different types of units as second generation replacements: The Sprinter series, as conventional DMUs for use on urban and longer-distance services, and the Pacer series as low-cost DMUs built using bus parts and intended for short-distance rural and branch line services. The Pacers were originally intended as a low-cost stopgap solution to the rolling stock shortage, with a maximum lifespan of 20 years. BR set a challenge to several companies to design a cheap, lightweight train similar to railbuses. Since then, 165 Pacer trains (totalling 340 carriages) have been built. By 2015, some of these were over 30 years old.
Demonstrator units toured the U.S., Northern Ireland, Belgium, Sweden, Thailand, Malaysia and Indonesia, without producing sales. However Iran purchased redundant Class 141 units, for use on suburban lines around Tehran until 2005.
The Pacer series was the result of an experiment to assess the viability of using bus parts to create a diesel multiple unit. 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). This was followed by the two-car prototype class 140, which was built in 1980 at British Rail Engineering Limited (BREL)'s Derby Litchurch Lane Works.
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 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.
The units were withdrawn from British Rail in 1997. Many were sold to Islamic Republic of Iran Railways but have been withdrawn and are left in disused sidings in Iran, whilst a few remain in preservation.
The next and largest Pacer class was the Class 142. This 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 142s were upgraded in the early 1990s to include 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. 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.
Class 143 and Class 144
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.
Then came a similar Class 144 unit, a Walter Alexander body on BREL underframe, which was introduced in 1987. A 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.
Advantages and disadvantages
The Pacers have often been criticised as being of poor quality. Instead of the usual bogies, Pacers use a basic four-wheel two-axle configuration which often results in a ride which is noisier and less comfortable than other trains. The lack of articulation can result in a rough ride, especially over points, and a loud squealing noise around tight curves. The lack of bogies also results in a more basic suspension, which can result in a bumpier ride; this has given rise to the nickname "nodding donkeys" owing to the trains' up-and-down motion on uneven track. The basic bench seating can also be uncomfortable. The early units, especially the Class 141s, were also especially unreliable.
Concerns were raised about safety after the 1999 Winsford crash, which involved a First North Western Class 142 Pacer running as empty stock was run into by a Virgin Trains Class 87 express after the Pacer unit had fouled the main line at Winsford, Cheshire on the West Coast Main Line. The body of the Pacer was severed from its frame, to which it was attached by wire straps, causing severe internal damage; the unit was written off. Twenty-seven passengers and crew were injured, four seriously. However, all passenger injuries were on the other train, as the Class 142 was running empty at the time.
On the other hand, the Pacers have been praised as a pragmatic solution at a time when budgets were tight, and have been credited with saving services on some rural lines which might otherwise have been withdrawn had only more expensive rolling stock been available. They have also proved economic to operate, achieving a fuel economy of 10 miles to the gallon.
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.
In July 2019, rollout of Northern's Class 195 CAF Civity units had begun on certain routes, which will allow refurbished Sprinters no longer needed on those routes to be used to replace Pacers instead.
These units are built out of upcycled London Underground D78 Stock, constructed between 1978 and 1981, which were in service on the District line until 2017. Conversion of the old stock to mainline railway use will involve re-using the aluminium bodyshells, traction motors and bogies from the D78 units and fitting them out with new diesel engines and interiors. The D-Train units underwent acceptance testing in 2015 and Vivarail pitched them to train operating companies (TOCs), especially those bidding for the Northern franchise. While no orders were received from Northern, Transport for Wales will replace its Pacers with a combination of five D-Trains and rolling stock cascaded from other train operators, and other TOCs have ordered D-trains to replace other outdated rolling stock: South Western Railway for the Isle of Wight's Island Line, and West Midlands Trains for the Marston Vale line
Porterbrook, which owns the Class 143 and Class 144 fleets, refurbished 144012 in 2014 to comply with the new legislation, dubbed the "144e Evolution" unit. However, no other units have been refurbished to this standard. 
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.
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- Pioneer Class 142 claimed for National Collection Rail Express issue 268 September 2018 page 76
- "Pacer trains 'could be used as village halls'". BBC News. Retrieved 13 June 2019.
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