London Underground battery-electric locomotives are battery locomotives used for hauling engineers' trains on the London Underground network where they can operate when the electric traction current is switched off. The first two locomotives were built in 1905 for the construction of the Great Northern, Piccadilly and Brompton Railway, and their success prompted the District Railway to buy two more in 1909, which were the only ones built to the loading gauge of the subsurface lines. Following this, a number of battery vehicles were built by converting redundant motor cars, with the batteries placed in the unused passenger compartment. One exception to this was made by the City and South London Railway, who used a trailer car to hold the batteries, and wired them to a separate locomotive.
From 1936, battery locomotives were built as new vehicles, although in most cases, some components, particularly the bogies and motors, were refurbished from withdrawn passenger cars. The batch of nine vehicles supplied by Gloucester Railway Carriage and Wagon Company between 1936 and 1938 set the standard for subsequent builds. Including this batch, 52 machines had been built by 1986, in six batches from four manufacturers, with one built at London Transport's Acton Works. Each new batch included some improvements, but most used electro-pneumatic traction control equipment made by GEC, and so could be operated together. The exception were three from the 1936 batch, which used an experimental Metadyne system, and the final batch of six, built in 1985, which used controllers manufactured by Kiepe.
Improvements since manufacture have included the replacement of low-level Ward couplers by buckeye couplers, which has resulted in less damage from shunting accidents, and the fitting of draught excluders and cab heaters for use in winter when the locomotives operate on sections of line above ground. A number of the machines were fitted with Automatic Train Protection (ATP) in-cab signalling equipment to enable them to work on the newly opened Victoria line, and later on the Central line after ATP was installed. More were fitted with Transmission Based Train Control (TBTC) for the Jubilee and Northern lines and Communication Based Train Control (CBTC) as part of the Four Lines Modernisation.
Early vehicles
The first two battery locomotives supplied for the London Underground were manufactured by Hurst Nelson and Co, who were based in Motherwell. They were delivered in August 1905, and were used during the construction of the Great Northern, Piccadilly and Brompton Railway, where they were numbered 1B and 2B. The vehicles were 50.5 feet (15.4m) long, with a tube-gauge cab at both ends. Braking and electrical control equipment was housed in a compartment behind one of the cabs, and the central section was lower, housing the 80 batteries, arranged in two rows of 40 either side of a central divide, which also supported metal covers for the battery compartments. The batteries were supplied by Chloride Electrical Storage Company. Each locomotive weighed 55 tons, and could haul a 60-ton load at 7km/h (4.3mph). They were not fitted with current collector shoes, as none of the rails were electrified during construction. Once their task was completed, they were moved by road to the Hampstead Railway.[1]
Encouraged by the performance of the vehicles, the District Railway purchased two of their own in 1909, which were larger as they were built to subsurface-gauge. The manufacturer was W. R. Renshaw and Co Ltd, who were based in Stoke-on-Trent in Staffordshire, and the vehicles were fitted with current collector shoes, so that they could draw power from the rails when it was available.[2] During the First World War, they were used as shunting engines at Ealing Common Depot, where power was always available, and so the batteries were removed, and subsequently neglected. New batteries could not be obtained, as batteries of this type were needed for submarines as part of the war effort. The vehicles were numbered 19A and 20A when supplied, but were renumbered as L8 and L9 in 1929, when the batteries were no longer fitted. As electric locomotives, they were upgraded several times, receiving two new types of motors in 1951 and 1955, and new traction control equipment in 1958. They continued to be used to move stores between Acton Works and Ealing Common Depot, until they were superseded by road vehicles in 1969.[3]
Conversions
The next batch of battery locomotives was made by converting existing stock. When it opened, the Central London Railway (CLR) had suffered from vibration problems, caused by the heavy locomotives, and had experimented with multiple unit operation, with motive power provided by converting four trailer cars to motor cars. Around 1910, two of these motor cars, numbered 201 and 202, were fitted with batteries, and worked on a number of lines in addition to the Central London Railway. In 1915 they were loaned to the Bakerloo line, when it was being extended to Queen's Park. Car 202 had its 'Nife' battery updated to one with 263 cells made by Edison Accumulator Ltd in 1924, while the number of cells in car 201 was increased from 200 to 238 in 1932. For working on other lines, they were fitted with outside shoes, since most lines used a four-rail system, whereas the CLR used only three. The vehicles were numbered L22 and L23 in 1929, and were scrapped in 1936 and 1937.[4]
When the City and South London Railway was being reconstructed in 1922, a number of "padded cell" trailer cars– so-called because of their lack of windows– were stripped out, so that lead-acid batteries and charging resistances could be placed in the resulting space. Each car was then coupled to an electric locomotive, and the batteries were connected to the shoe fuses of the locomotive. The current rail shoes were removed, so that the batteries did not energise the rails. Recharging was arranged at certain points, by means of switches and cables connected to the supply that normally fed the rails.[4]
Two Hungarian gate stock cars, which had previously been used as ballast motor cars, were converted to battery operation. When working as passenger vehicles on the Piccadilly line, they had been numbered 34 and 39. In 1929 they were transferred to the Hampstead line, where they were numbered 113 and 118, becoming L11 and L12 in 1936. Shortly afterwards, the numbers were swapped, so that L11 became L12 and L12 became L11. They used batteries made by DP Battery Company, each with 220 cells. The final conversion was of Bakerloo car 66, originally made by the American Car and Foundry Company, and fitted with a 220-cell DP battery weighing 6.5 tons in 1932. It was numbered L32, and was scrapped in 1948.[5]
Main battery locomotives
A battery-electric locomotive at Euston station, April 2006Locomotive L16 seen at West Ham station (District line platforms).LT battery-electric locomotives at Croxley Tip, 1971
In 1936, the decision was taken to purchase a batch of new battery locomotives, and an order was placed with the Gloucester Railway Carriage & Wagon Company for nine vehicles, six of which would be fitted with GEC traction control equipment, while the other three would be fitted with metadyne units. The GEC-fitted machines weighed 53.8 tons, and were numbered L35 to L40, while the Metadyne-equipped ones weighed an extra 2.2 tons, and were numbered L41 to L43. Both types, when pulling a 200-ton ballast train, could run at 30mph (48km/h) when supplied with power from the current rails, and at half that speed when working on batteries.[6]
The metadyne-fitted locomotives had new bodies, but the bogies and motors were removed from redundant Metropolitan line stock and refurbished at Acton Works. Similarly, the metadyne equipment was removed from an experimental train and reused. A metadyne unit consists of a rotating machine, which converts the constant voltage supplied by the battery to a constant current, which feeds the motor. The metadyne system is more efficient than conventional starting resistances, particularly when the locomotive starts and stops frequently, or when it needs to run for long periods at slow speeds. For cable laying work, the metadyne-equipped locomotives could pull trains of 100 tons at 3mph (5km/h) for considerable distances, without any sign of overheating. Despite the advantages, their complexity resulted in them becoming unreliable, and they were withdrawn in 1977.[7] L41 and L42 were scrapped soon afterwards, but L43 was used for testing purposes for a further three years.[8]
The locomotives fitted with GEC controls used an electro-pneumatic controller, with 28 steps, which allowed the four motors to be connected in series, in two parallel-series pairs, and all in parallel as the speed increased. Pairs of locomotives could be operated in multiple, and motors 1 and 3 or 2 and 4 could be selected if there was a failure of the other pair. As built, the vehicles were 54.3 feet (16.6m) long, and could pick up power either from a standard four-rail configuration, or the three-rail configuration of the Central London Railway, until it was converted to four rails in 1940.[6]
The next batch of seven vehicles were manufactured by R. Y. Pickering and Co Ltd, who were based in Wishaw, Scotland. The traction control equipment was by GEC, although the batteries had a larger capacity than the previous batch. The motors were reused from passenger stock which was being withdrawn at the time. One important improvement was the addition of runners and a lifting device, which enabled any battery cell to be removed from its rack and lowered to the ground through an aperture in the floor. This feature meant that the batteries could be changed without using an overhead crane in a lifting shop, freeing it for more important work. An eighth locomotive was built by staff at Acton Works in 1962, partly as an exercise to prove that the workshop could compete for this type of work. This vehicle was initially numbered L76, and took part in the Metropolitan Railway centenary celebrations, held on 23 May 1963, when it propelled a replica of the original inspection train of open wagons used by William Ewart Gladstone and other dignitaries.[9]
Metro-Cammell received the order for the next batch of thirteen locomotives, which were numbered L20 to L32. The first one was delivered on 8 December 1964 to Ruislip Depot. They were part of a programme to phase out the last remaining steam engines, but the Victoria line was also being built at this time, and some of the battery locos were fitted with automatic train operation (ATO) equipment, to enable them to work on that line. Traction control equipment was by GEC, with the batteries supplied by DP Battery Co Ltd. As with previous batches, parts of the locomotives were refurbished; in this case, the bogies, traction motors and compressors were supplied by Acton Works. Unlike earlier models, each vehicle was fitted with two compressors, allowing them to work singly. The last steam engines were withdrawn soon afterwards, and an order for five more battery locos was placed with Metro-Cammell in 1969. These worked on the Jubilee line construction, and were numbered L15 to L19.[10]
The construction of the Jubilee line and the Heathrow extension of the Piccadilly line required yet more works trains, and eleven more locomotives were ordered in 1972, with delivery in 1973. They were built at Doncaster Works by British Rail Engineering Limited. The motors were refurbished from redundant District line stock, but the bogies were new. Although based on the standard Z-type bogie used since the 1930s, they incorporated roller bearings, rather than white metal axleboxes and suspension bearings. Three of the locomotives were built to replace the three metadyne vehicles, but those were not actually withdrawn until 1977.[11]
A final batch of six locomotives was built by Metro-Cammell and delivered in 1985 and 1986. They incorporated all of the improvements made to the previous vehicles. For the first time, they were specified in metric units. New features included entry to the cabs through a central door, rather than a side door, strengthened windscreens with windscreen wipers, and the ability to charge the batteries while operating on electrified lines. One departure was the fitting of traction control equipment by Kiepe, which prevented them from working in multiple with any of the previous machines.[12] They were not a success, as five of the six had been withdrawn from service by August 1993, while a decision was made about their future,[13] and the sixth was withdrawn some time later. They were numbered L62 to L67, and all were still in store in 2002.[14]
All locomotives were built to a similar design, but with a number of variations included over the years of development. Numbers L41-L43 had Metadyne control gear.
The locomotives have a cab at each end and are built to the standard 'Tube' loading gauge so that they can work over all lines on the London Underground network. They are equipped with buffers and drawhooks, for coupling to standard main line vehicles. Earlier vehicles had hinged buffers, which could be raised upwards when not in use, but this job was arduous, and a programme of replacing them with retractable buffers was carried out. They were also fitted with a 'Ward' coupler, mounted at a height suitable for tube cars, but this made the locomotives prone to significant damage in shunting accidents. In 1980, two locomotives, L18 and L38, were fitted with buckeye couplings, as an experiment. These automatic couplings are mounted at the height of the main frames, and so shunting damage is significantly reduced. The success of the experiment led to buckeye couplings being retro-fitted to all locomotives built from 1964.[8] Additionally, they all have train air-brake equipment.
The body sides take the form of louvres to allow ventilation around the batteries, although most locomotives had four solid body panels on one side only. All body panels are hinged to allow the batteries to be removed. Following the withdrawal of steam engines, the vehicles often worked on open sections of line, rather than in tunnels, and the need to heat the cabs in winter became apparent. Draught excluders have been added to all cab doors, and additional heaters have been fitted into the cabs.[15]
The original livery was grey, but crimson lake was applied from the early 1960s using supplies of LT steam locomotive paint. This was changed to yellow in the early 1980s, which was deemed to be more safety conscious.[16]
Power
The locomotives can draw power from the 630V electrified rails like a normal tube train, or run on 320V DC traction batteries when the power is switched off. Since most of the traction motors were removed from redundant stock for fitting into the vehicles, Acton Works have had to convert them from 630V operation to work on 320V.[15] The lead-acid batteries are usually recharged inside a depot, although the 1985 batch of locomotives could recharge their batteries from the power rails while moving.[17]
Protection
All battery locomotives are fitted with tripcocks which are operated by trackside equipment if the train passes a signal at danger. Eighteen (L15–L21 and L44–L54) are also fitted with Central line Automatic Train Protection (ATP). When they were built, locomotives L25 to L32 were fitted with Automatic Train Operation (ATO) equipment, which allowed them to work on the Victoria line. The tripcock could be isolated, and a trip valve performed a similar function, except that it was operated by the ATO controller. A special setting was provided that allowed the vehicles to move if they were not receiving safety track signals, but the maximum speed in these circumstances was limited to 10mph (16km/h). By the mid-1980s, this equipment had ceased to be used, as works trains were only run on the Victoria line when engineers had possession of the whole line.[11] Subsequently, some locomotives (L27–L32) have been fitted with a new type of Victoria line ATP equipment which was designed by Metronet on behalf of Transplant, the operator of the fleet. This system was installed during 2007 at Ruislip Depot.[citation needed] It is compatible with the new Distance-to-Go Radio (DTG-R) ATP system which has been implemented on the Victoria line by Westinghouse Rail Systems.[18]
Ownership
The locomotives are, since the start of London Underground's PPP scheme, in the ownership of TransPlant. The locomotives are all based at Ruislip Depot.
The traditional use of these locomotives has been to haul trains using power from the rails until they reach the area where work is to be undertaken, where they switch to battery operation if the traction supply has been isolated. They are also used for transporting diesel powered equipment such as track tamping machines through tunnel sections. Normally one locomotive is marshalled at each end of the train, allowing the train to be reversed easily. The connections between different Underground lines often require reversals on route. Early locomotives were not allowed to operate on their own as they only had a single air compressor, but twin compressors were fitted to vehicles built from 1964 onwards, to allow single operation.[15]
With the building of the Jubilee line, diesel-powered locomotives manufactured by Schöma of Germany in 1996[19] took over some of the duties of the battery locomotives.
Metronet battery locomotives
In February 2006, Metronet received four small battery locomotives. These were named Walter, Lou, Anne, and Kitty, names that pun the name of the line they were bought to work on, London Underground's Waterloo & City line. They are used for hauling materials and equipment and were specially designed and built for work in narrow tunnels with tight curves and steep gradients. Clayton Equipment of Derby designed and built them[20] in about four months. The locomotives weigh 15tonnes each and have 200Volt DC motors providing 75hp (56kW) to each axle. As a fail-safe feature they have spring-applied disc brakes that are automatically applied if something goes wrong. Built-in cameras are connected to screens in the cab to make shunting easier.[21] Unlike the earlier battery-electric locomotives, these locomotives cannot draw power from the electrified rails. Under normal use this is not a problem because they are designed to work on engineering projects in tunnels where the power is cut off anyway, but it does mean they have to return to the depot to be recharged.
Related Research Articles
London Underground rolling stock includes the electric multiple-unit trains used on the London Underground. These come in two sizes, smaller deep-level tube trains and larger sub-surface trains of a similar size to those on British main lines, both running on standard gauge tracks. New trains are designed for the maximum number of standing passengers and for speed of access to the cars.
The Standard Stock title was applied to a variety of Tube stock built between 1923 and 1934, all of which shared the same basic characteristics, but with some detailed differences. This design is sometimes referred to as 1923 Tube Stock, 1923 Stock, or Pre 1938 Stock. Most of the Standard Stock was built to replace the first generation of "Gate Stock" Tube trains or to provide additional trains for extensions built in the 1920s and early 1930s. Standard Stock cars consisted of motor cars, with a driver's cab, behind which was a "switch compartment" occupying approximately one-third of the length of the car, plus trailer cars and "control trailers", with a driving cab but no motor. All were equipped with air operated sliding doors. The guard's door on the earlier trains was a manually operated, inward-opening hinged door.
The T Stock was a series of electric trains originally built in various batches by Metropolitan-Vickers and the Birmingham Railway Carriage and Wagon Company for the Metropolitan Railway in 1927–31 for use on electric services from Baker Street and the City to Watford and Rickmansworth, though rarely some worked on the Uxbridge branch.
The London Underground O and P Stock electric multiple units were used on the London Underground from 1937 to 1981. O Stock trains were built for the Hammersmith & City line, using metadyne control equipment with regenerative braking, but the trains were made up entirely of motor cars and this caused technical problems with the traction supply so trailer cars were added. P Stock cars were built to run together with the O Stock cars now surplus on Metropolitan line Uxbridge services. The trains had air-operated sliding doors under control of the guard; the O Stock with controls in the cab whereas the P Stock controls in the trailing end of the motor cars. The P Stock was introduced with first class accommodation, but this was withdrawn in 1940.
Diesel locomotives have seen limited use on the London Underground, largely because exhaust gases cannot be discharged when the vehicles are working in tunnels. A prototype diesel engine numbered DEL120 was built in 1939 from two 1915 stock motor cars, which was expected to be part of a batch of ten, but experience with battery locomotives showed that these were a better alternative. Three 0-6-0 diesels (DL81-DL83) were obtained in 1971, to replace the last steam engines, but were too short to operate the signalling system, and too heavy for some of the bridges. In 1996, fourteen diesels were supplied by Schöma of Germany, which were used during the construction of the Jubilee line tunnels. They were fitted with exhaust scrubbers, to enable them to work in the tunnels. To speed up track renewals on the subsurface lines, Class 66 locomotives have been hired in since 2006 to handle permanent way trains, but again suffer from being too heavy for some of the bridges. Because they are not fitted with tripcock safety devices, and pull trains much longer than the signalling system is designed for, they are restricted to slow speed running.
The London Underground 1960 Stock was a class of electric multiple unit for the London Underground Central line. Twelve motor cars were supplied by Cravens, and pairs were made up to four cars by the addition of two converted standard stock trailers. A production run of 338 motor cars was shelved, due to the time needed to assess the new features and the cost of converting the trailer cars. Some of the pre-1938 trailers were later replaced by 1938 stock trailers.
The London Underground 1967 Stock was a type of deep-level train that operated on the Victoria line of the London Underground from the line's opening on 1 September 1968 until 30 June 2011. It was also used on the Central line between Woodford and Hainault between 21 February 1968 and 1984, as the same automatic train operation (ATO) system was used on both lines.
An electric multiple unit (EMU) is an electric self-powered train, capable of operating in multiple with other EMUs and without the need for a locomotive; these are typically passenger trains with accommodation in every vehicle and a driving position at each end. The term can also be used to describe a train that is a permanent formation with a non-driving power car, such as the Advanced Passenger Train. As of December 2010, two-thirds of the passenger carriages in Great Britain are formed in EMUs.
Electric locomotives were first used on the London Underground when the first deep-level tube line, the City and South London Railway (C&SLR), was opened in 1890. The first underground railways in London, the Metropolitan Railway (MR) and the District Railway (DR), used specially built steam locomotives to haul their trains through shallow tunnels which had many ventilation openings to allow steam and smoke to clear from the tunnels. It was impractical to use steam locomotives in the small unvented tubular tunnels of the deep-level lines, and the only options were rope haulage or electric locomotives.
The London Underground 1935 Stock was an experimental train design by Metropolitan Cammell in London. Twelve two-car units, marshalled into four six-car trains, were built. They served as the prototypes for the later 1938 Stock.
The 1920 Tube Stock consisted of forty cars built by Cammell Laird in Nottingham, England. These cars were the first new tube cars to be built with air operated doors. The batch consisted of twenty trailer and twenty control trailer cars, which were formed into six-car trains by the addition of twenty French motor cars built in 1906 and modified for air-door operation. They initially ran on the Piccadilly tube, but in 1930 were considered to be drab, compared to new stock being delivered at the time. The motor cars were therefore replaced by Standard Stock units, built in 1927, and the 1920 cars were refurbished. They were transferred to the Bakerloo line in 1932, and continued to operate until 1938.
The Central London Railway Stock were electric multiple units composed of trailers that had been converted from carriages designed to be hauled by electric locomotives with new motor cars. The Central London Railway opened in 1900 with electric locomotives hauling wooden carriages, but the heavy locomotives caused vibrations that could be felt in the buildings above the route. It was found that conversion to electric multiple units solved the problem, so new motor cars were bought and replaced all the locomotives by June 1903. Trains normally ran with six-cars, four trailers and two motor-cars. Some trailers were equipped with control equipment to allow trains to be formed with three cars.
Sleet locomotives were redundant London Underground cars converted to help with the removal of ice that built up on the conductor rails. The main batch of eighteen tube-gauge locomotives were built between 1938 and 1941 from motor cars originally built in 1903. They were refurbished in the 1960s using equipment removed from redundant T-stock vehicles, and were joined by a pair of surface-gauge locomotives in 1961.
A metadyne is a direct current electrical machine with two pairs of brushes. It can be used as an amplifier or rotary transformer. It is similar to a third brush dynamo but has additional regulator or "variator" windings. It is also similar to an amplidyne except that the latter has a compensating winding which fully counteracts the effect of the flux produced by the load current. The technical description is "a cross-field direct current machine designed to utilize armature reaction". A metadyne can convert a constant-voltage input into a constant-current, variable-voltage output.
Ealing Common Depot is a London Underground railway depot on the District line, located between Acton Town and Ealing Common stations in west London, England. It is the oldest of the main depots on the Underground, having been built in 1905, when the District Railway was upgraded for electric traction. All depot facilities were moved there from Lillie Bridge Depot, and it was known as Mill Hill Park Works. It subsequently became Ealing Common Works, and its status was reduced to that of a depot in 1922, when Acton Works was opened, and took over responsibility for all major overhauls. Most of the functions of Acton Works were devolved back to the depots, including Ealing Common, in 1985.
Hurst, Nelson and Company Ltd was a railway rolling stock manufacturer based in Motherwell, Scotland. The company also built many railway wagons, as well as trams and trolleybus carosseries for several local authorities.
Metropolitan Railway electric multiple units were used on London's Metropolitan Railway after the lines were electrified in the early 20th century.
District Railway electric multiple units were used on London's Metropolitan District Railway after the lines were electrified in the early 20th century.
Departmental locomotives on the London Underground consist of vehicles of a number of types which are used for engineering purposes. These include battery locomotives, diesel locomotives, electric locomotives, sleet locomotives, pilot motor cars and ballast motor cars. Details of the first four types are covered elsewhere. Pilot motor cars and ballast motor cars are generally vehicles which have been withdrawn from passenger service, but continue to be used by the engineering department. Pilot motor cars are used to move other vehicles around the system, while ballast motor cars are used to haul ballast trains and engineering trains.
Acton Works is a London Underground maintenance facility in West London, England. It is accessed from the District line and Piccadilly line tracks to the east of Acton Town station, and was opened in 1922. It was responsible for the overhaul of rolling stock, and gradually took on this role for more lines, until the formation of the London Passenger Transport Board in 1933, when all major overhauls of underground vehicles were carried out at the works. By 1985, when rolling stock had become more reliable and maintenance intervals had increased, this function was devolved to depots on each line. Subsequently, Acton continued to overhaul major items after they had been removed from trains at the depots, and tendered for work, which included the conversion of the A60 Stock to One Person Operation. It is likely to be reorganised and expanded to house the departments displaced from Lillie Bridge Depot which is being demolished as part of the redevelopment of Earls Court Exhibition Centre.
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