George Stephenson, engineer of the Stockton and Darlington railway, is renowned for his early steam locomotives. Yet, in 1847, the year before his death, he advised a visitor that “I have the credit of being the inventor of the steam locomotive, but I tell you, young man, I shall not live to see it, but you may, when electricity will be the great motive power of the world.”
Stephenson would have been aware of Michael Faraday’s discovery of electromagnetic induction in 1821, and of the first practical electric motors which were produced in the 1830s. In 1842 (183 years ago), Robert Davidson trialled the first ever railway electric locomotive between Edinburgh and Glasgow. However, this was not a success as it only managed 4mph and its batteries were not rechargeable.
To his credit, Stephenson saw the potential of electric traction from these early experiments. Yet Britain’s early railways focused on improving steam traction, leaving those outside the UK to develop electric rail vehicles. In 1866, Siemens developed a dynamo that paved the way for industrial-scale electricity generation. In 1879, Werner von Siemens in Germany demonstrated the world’s first electric passenger train at an exhibition in Berlin.
In the USA, heavy-duty electrical engineering developments resulted in America having 250 electric streetcar systems by 1893. A pioneer in the development of electric streetcars was Frank Sprague who developed nose-suspended, axle-hung traction motors and multiple unit control.
The first UK electric train was the two-foot-gauge 1883 Volks electric railway along Brighton’s seafront which was originally electrified at 50V DC. This is now the world’s oldest operational electric railway. In 1885, Blackpool opened Britain’s first electric tram system. This used a conduit system to pick up the electric current from the third rail below the road surface. However, this was vulnerable to Blackpool’s sands and, in 1899, was converted to a 550V DC overhead tram wire.
Early underground railways
The UK’s first heavy-rail electric railway opened in 1890. This was the 3.2-mile City & South London Railway (C&SLR) which ran from a station near Bank to Stockwell and was also the world’s first deep tube railway. This had a 75kW 3.6-metre-long locomotive with windowless coaches and was powered by a 500V DC third rail system. Subsequently, part of it was converted to what became London Underground’s standard fourth rail system. This kept the return current from the running rails and so prevented corrosion in metal tunnel linings.
The C&SLR electrification used American traction technologies which were adopted by subsequent underground railways. It was followed by the Waterloo and City Line which opened in 1897 which used a 530V third rail system. Although it used American rolling stock, Siemens provided the electrical generation and distribution equipment
The world’s first Metro railway, the subsurface line between Paddington and Farringdon was electrified in 1902. This was steam-hauled when it opened in 1863. By 1910, deep tube lines in central London had opened as follows: Central (1900), Bakerloo (1906), Piccadilly (1906), Northern via Bank (1907), and Charing Cross (1909).
The development of the Underground railway network had a significant impact on early main line electrification. This demonstrated the reduced cost and improved acceleration of electric traction and resulted in many railways using the third-rail system.
Early conductor rail electrification
The first UK main line to be electrified was the Liverpool Overhead Railway which used a 525V DC third rail system. It was also the world’s first elevated railway when it opened in 1893 and was subsequently extended over the full 10km length of Liverpool’s docks. Steam-haulage was too heavy for its overhead structures and presented a fire risk to the dock’s inflammable cargos.
Liverpool also had the first railway to be converted from steam to electric operation. This was the 6km Mersey Railway between Birkenhead and Liverpool which opened in 1886. However, the smoke from frequent hard-working steam trains in the long, steeply graded Mersey tunnel resulted in passengers deserting trains for the ferries. Westinghouse considered that the railway would be profitable with electric traction and so funded its electrification which was commissioned in 1903. This was a 600V DC fourth rail system.
Another world-first for Liverpool was the 37km electric inter-urban railway to Southport operated by the Lancashire and Yorkshire Railway (L&YR). It was initially a 600V DC fourth rail system though was later converted to 625V DC third rail. By 1915, lines to Ormskirk and Headbolt Lane had been electrified giving Liverpool 76 route km of electrified railways.
The North Eastern Railway (NER) decided to electrify its lines to Tynemouth and South Shields as it faced stiff competition from the new electric tramways. This 600V DC third rail electrification was commissioned in 1904. This reduced costs by 50% and doubled passenger numbers. In later years British Rail (BR) would describe this as the “sparks” effect.
In 1914, the London and North Western Railway (LNWR) ran its first electric service between Willesden Junction and Earls Court. With work delayed by the First World War, electric services between Euston and Willesden Junction did not start until 1917. Electric trains reached Watford in 1922, the same year that the Broad Street line was electrified at 630V DC. Where there was inter running with Underground trains, the negative fourth rail between the running lines was bonded to the running rails at earth potential.
Electric trams taking passengers from the railways was also the impetus for the London & South Western Railway (LSWR)’s ambitious electrification programme which electrified over 100km of services from London Waterloo with the 600V DC third rail system. This included services to Wimbledon, Shepperton, Hounslow, and Surbiton on which electric trains were introduced in 1915 and 1916.
The L&YR electrified the Manchester to Bury line in 1916. This was intended to be the start of Manchester’s suburban line electrification programme. However, the Great War and subsequent economic difficulties stopped more lines being electrified. This had a third rail system energised at 1.2kV DC which was the maximum third rail voltage permitted by the Board of Trade and so had a specially profiled side-contact conductor rail encased within a timber guard.
Early overhead electrification
The UK’s first high-voltage overhead railway was from Lancaster to Morecambe and Heysham which totalled 34 single track kilometres (stk). This was electrified by the Midland Railway at 6.6kV 25Hz AC in 1908 to assess the practicality of further electrification. Various lessons were learnt from this including optimum wire tension and stagger. Its trains had commutator AC traction motors as, at the time, on train high-current rectification was not practicable.
Although this trial was a technical success, there was no further MR electrification. However, these lines were again used as a trial in 1952 for 25kV AC overhead electrification.
6.6kV AC overhead electrification was also the choice of the London Brighton and South Coast Railway (LBSCR) after it obtained powers to electrify its suburban lines in 1903. The company electrified 75 route km with this overhead system. Its first electric service operated between London Bridge and Victoria via Peckham in 1909 later Crystal Palace and West Croydon. This was a success as, with frequent station stops, improved acceleration halved journey times. However, in 1925 the LBSCR became part of the Southern Railway (SR) which decided to standardise on third rail electrification and so had converted all this overhead line system to third rail by 1929.
The Great Central Railway (GCR)’s decision to build a large dock complex near the small settlement of Immingham required the company to bring dockers from neighbouring towns. Hence it built the 11km Grimsby & Immingham electric railway. This had a 500V DC system with a simple trolley wire. As GCR had power stations powering cranes and lock gates, the railway had a cheap supply of electricity. Its substations, supplied by Siemens, generated electricity at 6.6kV AC which was then transformed and rectified to 500V DC using Westinghouse rotary converters.
1915 saw the first electrified freight railway. This was the 30km line from Shildon to Middlesborough which had heavy mineral traffic. To provide sufficient power this was electrified at 1.5 kV DC and had a double copper contact wire. It used 820kW 76 ton 0-4+4-0 locomotives based on American practice which could haul a 1,400-ton train on the level at 40km/h. Each bogie had two 750V motors connected in series. It was found that five electric locomotives could do the work of 13 steam locomotives. They were also less expensive to maintain with twice the distance between repairs than a steam locomotive.
Up to 1956
After these early schemes, the two world wars constrained investment in electrification except for the SR’s third rail electrification programme. The SR was a 100% privately-owned company which, from 1925 benefited from low-interest rate UK Government loans intended to stimulate infrastructure investment.
This enabled the SR to make a strategic investment in a steady rolling programme of electrification between 1925 and 1939. When war brought this programme to a halt, 2,814 stk of third rail had been electrified which is almost 70% of the current Southern DC third rail network.
The total cost of this programme was £20 million. In today’s prices this is around £500 million or £0.2 million per stk. Thus, the SR delivered a profitable, low-cost electrification programme which attracted more passengers due to the better acceleration of electric trains which, for example, enabled more station stops to be made. Electric trains were also far cheaper to operate than steam trains.
This was the only example of a rolling electrification programme in the history of Britain’s railways.
With the aftermath of the war and railway nationalisation, there was no further third rail electrification until 1959. Thereafter, a further 1,349 stk of Southern third rail electrification was delivered up to 1994 to bring the third rail network up to its current 4,163 stk. However, instead of a continuous rolling programme, this was delivered as a series of projects that had to be individually approved.
Between the wars there was little electrification north of the Thames. There was some expansion of the Newcastle and Liverpool third rail systems and, in 1931, the 14km railway between Manchester and Altringham was electrified with an overhead 1.5kV DC system.
In the 1930s, the London & North Eastern Railway (LNER) started work on two 1.5kV DC overhead electrification schemes which had to be deferred until after the war. One was Liverpool Street to Shenfield which was eventually electrified in 1949 and extended to Chelmsford and Southend Victoria in 1956. The other was the steeply graded line between Manchester and Sheffield via Woodhead which carried coal trains. This was the first UK electric railway to use regenerative braking as the electricity generated by braking trains on the descents on both sides of Woodhead tunnel fed current into the overhead wires.
Adopting 25kV AC
In 1952, a report concluded that all future electrification should be the overhead 1.5 kV DC system except for extensions to the Southern third rail system. Yet just four years later another report concluded that overhead 25kV AC should be the standard. This was the result of the development of 25kV AC electrification in Europe in the early 1950s, the availability of reliable high-current mercury arc rectifiers and that high-voltage AC systems offered a significant cost reduction by reducing the number of electrical substations required. This also followed successful trials on the Morecambe and Heysham line which, as a trial in 1952, was the first UK line to be electrified at 25kV AC.
The 1956 BR Modernisation Plan covered a 15-year period and envisaged an extensive electrification programme as part of its plan to replace steam locomotives as shown in Table 1. The plan envisaged the purchase of 1,100 electric locomotives and regarded diesel traction as a halfway house to electrification.
Within its 15-year period, the plan envisaged 400 route km of Southern third rail electrification and 1,500 route km of 25kV overhead electrification (as shown in the table), though it noted that many more main-line services had a traffic density that gave them a good economic case for electrification.
By 1970, these routes had all been electrified except for lines out of Kings Cross and beyond Colchester. Much of the London suburban electrification was able to use structures of the original 1.5kV DC overhead system. When these lines were converted to 25kV AC electrification a safety concern was that overhead linemen would continue to use the thick rubber gloves that they used on 1.5kV DC lines. Fortunately, this was not a problem.
Due to restricted clearances, many of the London and Glasgow suburban lines were electrified at 6.25kV AC which requires electric multiple unit (EMU)s to have dual-voltage transformers.
Six weeks after the introduction of the new electric service in 1960, the Glasgow EMU fleet was withdrawn from service after five transformer failures including two explosions. It was found that the secondary transformer windings could not withstand over-voltages from rectifier backfires and irregular operation of the dual voltage system. In just two months, a modified transformer was satisfactorily tested. Seventy-seven motor coaches were then fitted with the new transformers within five months to enable electric services to resume after 10 months.
The 13km Styal line near Manchester was electrified in 1958 as a trial line for 25kV EMUs, locomotives, and fixed equipment. This was the first stage in the Manchester / Liverpool to Euston electrification which was delivered in stages from the north to London. Its completion in 1966 enabled electric trains to operate a new high-speed regular interval timetable which reduced the journey time between London and Manchester to 2 hours 30 minutes, saving nearly an hour.
Further OLE electrification
In 1981, a joint Department of Transport / BR review concluded that a long-term rolling programme of electrification would be profitable. Unfortunately, this was not to be. So, as shown in the graph, electrification was done in fits and starts. Between 1985 and 1991, BR delivered the East Coast Main Line (ECML) electrification to time and budget at a cost of £0.4 million per stk at today’s prices as reported in Issue 158 (December 2017). Before and after this project, BR was able to deliver smaller schemes to ensure that skilled electrification teams were not disbanded.
After an average of 220 stk of electrification per year was delivered in BR’s final 15 years, little electrification was delivered in the first 15 years of rail privatisation.
2010 saw the first significant electrification project for 14 years. This was part of the new Airdrie to Bathgate line which was completed to time and budget. As the line was electrified as it was built, its electrification was at a significantly reduced cost with no disruption. This lesson was not considered when the East West rail project was authorised.
A few years later there was a massive spike in electrification delivery because of the Great Western Electrification Programme (GWEP) and other schemes announced in 2009. By 2012, it was planned to have no less than 11 simultaneous electrification projects in 2016. This was inevitably inefficient with mistakes made due to lack of experience. GWEP also did not take account of BR experience and so made unduly onerous design assumptions which significantly reduced installation productivity.
By 2016, GWEP was up to three years late and its costs had almost doubled. It was eventually delivered at £3.4 million per stk which, at today’s prices, was eight times more than the BR ECML electrification. As a result, the Westminster Government curtailed GWEP by omitting Swansea, Oxford, and Bristol, and cancelled the planned Midland Main Line electrification. Their view was that electrification was the wrong technology as bi-mode trains can deliver the same benefits.
The Scottish Government had a different view. Around the same time, the Edinburgh to Glasgow electrification programme was significantly overspent. Yet in Scotland the benefits of electrification were recognised so the question was asked “was what can be done to fix this?” Other schemes in Scotland were then delivered in a cost-effective manner as part of a steady rolling programme.
The Welsh Government also has a different approach to rail electrification as its Core Valley Lines (CVL) are the first to have large-scale discontinuous electrification. The CVL network is 215 track km of which 170km has been electrified and so uses battery EMUs.
Why rail electrification?
In 2021, the Railway Industry Association (RIA) published its ‘Why Rail Electrification?’ booklet. In its foreword, Professor Felix Schmid, then chair of the IMechE’s Railway Division, states:
“Today’s high-speed railways, intensive suburban services, and high-capacity metro operations are only possible with electric trains. Their high acceleration rates result in lower journey times or allow more stops to serve the market better. Freight also benefits, thanks to longer trains requiring fewer paths. Better acceleration and higher speeds improve integration with passenger services.”
This history of electrification explains why, compared with the European average of 57% only 38% of the UK network has been electrified in an inefficient boom and bust manner. It is a story of lost opportunities due short-term thinking by decision makers who have little understanding of what an electric railway offers.
Currently, there is no money for electrification, and some believe that bi-mode trains and battery technology has made further electrification unnecessary. This view is influenced by the shadow of the awful GWEP programme, despite electrification cost savings since then. Yet whilst the CVL shows there is a role for battery traction, a whole system view needs to be taken to determine the best traction policy.
It is thus hoped that when Great British Railways brings track and train together, it will have the authority to decide how best to invest available funding in both infrastructure and trains as did the SR in the 1920s and BR did for the ECML.
Much of this article is derived from the book ‘Lines of Power’ by John Buxton and Donald Heath which is recommended further reading.
Image credit: David Shirres