Electric multiple units
The great bulk of electrified lines inherited by BR comprised the Southern Railway network that used the third rail current collection system.
And for some years after nationalisation, activity was confined to finishing schemes (such as the Woodhead and Shenfield projects) that had been started by the LNER but held up during wartime.
The rolling stock provided for the Shenfield services was built to a pre-war design by private contractors, and equipped with English Electric traction equipment. When first built, the trains were operated using 1,500V direct current (DC) overhead line collection, but from 1960 they were converted to the AC format.
The first units equipped to use the newly standard 25kV alternating current (AC) overhead power line system were delivered in 1958 for use on the London, Tilbury & Southend lines, although initially they were allocated to services between Liverpool Street to Southend Victoria as this was converted DC to AC power. They had been built at the BR workshops at Doncaster and York, following the standard Mk 1 coaching stock design with electrical equipment supplied by English Electric.
In Scotland, electrification of North Clyde and Cathcart circle routes in 1960 saw the introduction of the striking ‘blue trains’ that were deliberately liveried to stand out from the down-at-heel steam-hauled services they replaced.
The three-car units were manufactured locally by Pressed Steel, and were based on the Mk 1 bodyshell design with electrical components made by Metropolitan-Vickers. They had many features that made them ‘state of the art’ at the time of their introduction, including the use of pneumatically operated sliding passenger doors - the only Mk 1 based EMU to use this feature.
Of note was the introduction in 1962 of the first 100mph units for Clacton services, built by BR at York. The traction motors were supplied by GEC and Commonwealth bogies were fitted to reflect the higher speed required.
In 1963, the first EMU based on the Mk 2 bodyshell was introduced. They were built at Derby using English Electric traction equipment for use on commuter services from London Euston, but were restricted to 75mph maximum speed.
Similar units were constructed at York, with the final type being introduced in 1976 for the newly electrified Great Northern suburban services, with speed upgraded to 90mph. This was the last unit class to be built with slam doors.
Also in 1976, a type that remains in the current-day fleet was introduced and used as a standard inner suburban train. These were the first second-generation EMUs to be constructed, and featured an aluminium alloy body. Dual-voltage capability was available as required on the GN route to Moorgate. Another innovation was that they were the first units in Britain to have multi-function Tightlock couplers, allowing coupling and the connection of control electric and air supplies to be carried out from the cab.
From 1981, the Mk 3 bodyshell was used for both AC and DC units, although the length was reduced to 19.83 metres. A mixture of GEC and Brush electrical equipment was supplied, with some recovery of previously used equipment for third rail vehicles. The trains were constructed at York, and remain in service today. Common features are Tightlock couplers, disc brakes and sliding doors, although the vehicles have dated as no air-conditioning was fitted.
The final AC electric type specified by BR was in line with the policy of encouraging alternative suppliers, with a small fleet of Class 323 units built by Hunslet TPL in 1992 for use in the West Midlands and Greater Manchester. The West Yorkshire Passenger Transport Executive had also wanted to use the type on the newly electrified Airedale lines, but BR did not secure authority from the DfT.
British Railways inherited a significant fleet of electric units powered by the DC system. As these units became due for replacement, the standard Mk 1 vehicle formed the basis of the rolling stock built, including that for newly electrified routes such as the major Kent Coast scheme (310 miles equipped by 1962). Motor coaches had two 250hp English Electric traction motors that were used through the Mk 1 fleet.
The Bournemouth electrification completed in 1966 entailed most of the rolling stock being sourced from locomotive-hauled Mk 1 coaches dating from 1951. But by 1986 the vehicles were in poor condition and a fleet of new units was authorised based on the Mk 3 bodyshell. However, the ever-thrifty Southern Railway inheritance resulted in the traction equipment from the motor coaches of the original sets being re-used.
Network SouthEast was created as a result of the BR Sector reforms in 1982. By now there was an urgent need to replace ageing inner suburban vehicles, for which the Networker was designed as a replacement. In 1988 an Invitation To Tender was issued that covered a requirement for 710 units and by 1994 a total of 147 sets had been delivered for Kent suburban services. An express version was also developed, and today these are allocated to King’s Cross outer suburban workings.
There was a change from the then standard use of GEC (previously English Electric) traction motors, with the unit construction divided between BREL at York and GEC Alstom. Former sets used Brush electrical equipment.
There was a long delay before the new privately owned train operating companies were ready to order new rolling stock, but for electric units products were available from Adtranz (later Bombardier), Alstom and overseas builders such as CAF and Siemens.
Bombardier acquired Derby’s Litchurch Lane works from Adtranz in 2001, and was offering the Turbostar and Electrostar product as well a metro design it had developed for use on the London Underground. The Electrostar had been ordered in quantity by the LTS, Southern and South Eastern franchises.
Alstom had acquired the Metro-Cammell works at Washwood Heath, Birmingham, as a platform to bid for the construction of rolling stock in Britain and secured an important order from Angel Trains (on behalf of Virgin) to construct the Pendolino fleet for West Coast operations. It also supplied a limited number of third rail units for Gatwick Express and South West Trains - in both cases financed by Porterbrook.
At one time it looked as though Alstom would challenge Bombardier in the EMU market, with its Juniper product. But after the problematic performance of these Class 458 trains supplied to South West Trains in 1998, when the time came to replace the Mk 1 slam door fleet the operator switched its supplier to Siemens.
This was a blow from which Alstom operations in the UK did not recover and the Metro-Cammell plant it had acquired in 1989 was closed in 2005 after construction of the Class 390 Pendolinos was completed in the UK.
Siemens has a long relationship of trading with UK railway companies and in an ongoing and successful partnership with the Spanish builder CAF its electrical equipment was used for trains ordered by Heathrow Express and by the then Northern Spirit franchise to replace elderly rolling stock on the Airedale routes. The Heathrow Express units were purchased outright by airport owner BAA, while Angel Trains provided finance for the Airedale vehicles.
Angel Trains developed a partnership with Siemens to exploit the UK market, and the manufacturer’s four-car AC Desiro type was chosen by the Great Eastern franchise to replace units used on longer-distance services to Clacton. The type also attracted an order from Heathrow Express for use on the Airport Connect stopping service (again a direct purchase).
The need for higher-performance rolling stock to conform to West Coast Main Line pathing requirements resulted in more orders for the Class 350 Desiros, funded by Angel Trains.
Thirty sets were acquired in 2005, and these were soon enhanced by a further 37 sets, this time financed by Porterbrook and delivered in 2009. The enhanced fleet was required to provide rolling stock for West Coast semi-fast services that were transferred to the London Midland franchise.
This year, a further 20 sets were ordered for delivery in response to traffic growth, and to provide rolling stock for the newly electrified TransPennine Express between Manchester Airport and Edinburgh/Glasgow. The latter vehicles have been upgraded to offer 110mph maximum speed.
The decision to replace Mk 1 rolling stock on routes operated by South West Trains did not leave a long timeframe to acquire new trains. As a result, the Siemens Desiro type was again chosen, and the fleet replacement programme was completed in 2006. In total, Angel Trains funded 845 coaches, comprising 45 five-car express units and 155 four-car outer suburban sets.
Another significant Desiro order was secured from ScotRail, with the backing of Transport Scotland. Thirty-eight three-car and four-car 100mph units were delivered for introduction into service in 2010, with funding from Eversholt Rail.
The provision of 1,140 coaches required for upgraded Thameslink services proved controversial, after the tendering process resulted in the contract being awarded to Siemens.
There were questions about whether the evaluation of the bids reflected the societal cost of Britain’s sole passenger carriage manufacturer (Bombardier) losing the order. Subsequently, it was revealed that the need to provide finance to purchase the rolling stock (for lease to the Thameslink operating company) had put Bombardier at a disadvantage, because Siemens had a much stronger credit rating and could therefore raise finance more cheaply.
But the decision looked at odds with common sense from a UK trading perspective, and it resulted in a scramble to find orders for further Class 377 units to prevent the Derby works from closing. It also put down a marker about the procurement award for the Crossrail fleet of 585 vehicles, which was duly placed with Bombardier in early 2014.
Earlier, Transport for London had dropped plans that required the vehicles to be financed by the manufacturer, and instead secured a £500 million corporate loan facility with the European Investment Bank.
Hitachi has made a successful entry into the UK market, with lease finance provided by Eversholt. In 2009, it completed the delivery of 29 six-car high-speed units for the Southeastern franchise, capable of 140mph maximum speed to provide rolling stock for the HS1 domestic services.
Also in 2009, the DfT chose the Agility Trains consortium (comprising Barclays Private Equity, Hitachi and John Laing) as the supplier of replacement HSTs. An attraction was that 70% of the contract value would be placed in the UK and that Hitachi would construct an assembly plant at Newton Aycliffe.
The specification for the rolling stock changed following the decision to electrify the Great Western Main Line, although the bi-mode capability has been retained to enable trains to run to destinations that are not equipped with overhead wiring.
The order for the Class 800 bi-mode trainsets will provide 13 nine-car and ten five-car vehicles for East Coast operations and 36 five-car units for the Great Western. The allocation of the electric-only Class 801 type is 30 nine-car and 12 five-car for East Coast and 21 nine-car for Great Western. There is flexibility in the conversion of bi-mode formations to electric, but only if enhanced route electrification occurs. The order totals 866 cars that are to 26m long with a speed capability of 125mph.
Hitachi has also been successful with a new product described as the AT200 Commuter, designed with 23m coaches and a maximum speed of 100mph.
The type has been chosen by Abellio as part of its successful bid to operate the ScotRail franchise from April 2015. Seventy units will be supplied (with an option for a further ten), formed as 46 three-car and 24 four-car trains. They will run on the newly electrified Edinburgh-Glasgow line via Falkirk, as well as on the Stirling-Alloa-Dunblane lines, and will be cleared to run throughout the wider network, which is currently being electrified.
Diesel multiple units
The initial attraction of a diesel-powered train was the realisation that thermal efficiency would reduce operating costs, as well as the capacity for driver only operation (DOO).
A prototype had been demonstrated as early as 1931, built by the Tyneside firm of Armstrong Whitworth in the form of a diesel electric multiple unit. But the LNER showed little enthusiasm to extend the project, despite statistics that showed operating costs of 6.5p per mile compared with steam railcar operations of 9.1p, and a traffic availability of 86% compared with 70% for steam.
