London Underground Electric Train

Piers Connor

• Publisher: Crowood
• Year: 2015
• ISBN:
  9781785000140
• Topic: Technology & Engineering
• Subtopic: Rail Transportation
• Index: Technology & Engineering

The London Underground Electric Train tells the story of the development of electric traction on the London Underground system. It combines technical knowledge, historical context and practical experiences, and covers the history of underground lines since the opening of the first deep-level underground rail system in the world in 1890: the City & South London Railway. The evolution of train design, including power, lighting, heating and design of the Underground cars is also covered along with the development of operational, engineering and safety devices on trains. Highly illustrated with period and new photography and technical diagrams, this book is a reference work for electric traction and underground rail enthusiasts.

CHAPTER ONE

HERITAGE

THE LONDON UNDERGROUND

The London Underground, known as ‘The Tube’, is the oldest of the world’s many urban rapid transit systems, the first section opening on 10 January 1863. Its wonderful heritage was celebrated in style for its 150-year anniversary in 2013, including a visit by Her Majesty The Queen and members of the Royal Family and a re-enactment of steam operation between Edgware Road and Moorgate over part of the original route. The Underground now has eleven lines and serves 270 stations, which provide services for up to twenty hours a day. The system is operated by TfL (Transport for London), which is also responsible for the provision of some main line rail services (the ‘Overground’), London area bus service franchising and surface transport facilities in the greater London area, amongst other things.

The region known as Greater London has an area of 618 square miles (1,600km²) and a population of over 7 million. Over a million people travel into central London each day for work and over 60 per cent of these use the London Underground system. Over the last fifteen years there has been a 70 per cent increase in the demand for travel on the Underground so that, more than ever before, London relies upon the Underground system as part of the social and economic structure of the city. Recently, the number of passenger journeys exceeded 4 million a day.

Tube and surface stock on test at the Bombardier factory in Derby. The smaller train on the right is 2009 Tube Stock for the Victoria Line, while the larger train is the S (subsurface) Stock. The tube car floor is about 300mm (12in) lower than the subsurface stock car and the roof is 800mm (31in) lower. A surviving tradition on the Underground is to identify sub-surface stock train types by letters and Tube Stock by the date of delivery, or close to it. EDWARD ROBINSON

The central area of London is enclosed by the major mainline railway termini and the Underground’s Circle Line that connects them. This area within the Circle Line forms the commercial heart of the capital. The area known as ‘The City’, east of Holborn, is the financial district, while the West End contains the principal shopping and entertainment areas. Until the beginning of the twentieth century there was virtually no penetration of these areas by railways but then the various deep-level Underground ‘tube’ lines were opened and there is now a network of lines covering both the City and West End zones and connecting them with many of the suburbs. The routes going out to the suburbs rise to the surface outside the central area and, in fact, some 55 per cent of the London Underground route mileage is in the open.

The Greater London area is geographically divided into two halves by the River Thames, which flows west to east across the city. In the north–south division that this causes, by far the greater proportion of the Underground system is located in the northern area. Of the 270 stations serving the system only twenty-nine are located south of the Thames, due partly to old railway company politics and partly to the nature of the subsoil in the area, which rendered tube construction difficult and expensive. In contrast with the freight-rich railway companies north of the river, the southern companies depended very much on local passenger traffic for revenue and provided a dense network of frequent services, which were electrified almost entirely by 1930. The Underground was not needed in this area.

One of the features of the London Underground is that it operates rolling stock of two different sizes. This is because, over the long period of its development, two different methods of tunnel construction were adopted.

Cross-section of the 1863-built Circle Line tunnel at Baker Street station (now Platforms 5 and 6) showing the original cut and cover construction that is still in place today. The arch and side walls are brick. The station tunnel was provided with angled shafts at intervals to admit natural light, seen on the left section. These shafts have since been covered but they now have artificial lighting to replicate their original use. The road above is the Marylebone Road. Note that the track shown is mixed 7ft (2m) and 4ft 8½in (1.4m) gauge, to accommodate trains from the Great Western Railway as well as other operators. This section is wider at 45ft 1 in (13.7m) than the inter-station sections, where the internal width is 28ft 6in (8.7m). Later tunnels were only 25ft (7.6m) wide as they did not need to accommodate the broad-gauge track.

TWO SIZES OF TRAINS

The original tunnelling method, used for the Circle Line and its extensions (now the Metropolitan and District Lines) is known as the ‘cut and cover’ method. With this method, a cutting is dug along the line of the route just deep enough to take a main-line-sized train and its track. When completed, the tunnel is roofed over and the surface restored, often with a roadway. Most of the resulting tunnels are wide enough to take two tracks, except at stations, where they are widened to take platforms and stairways. Because of their proximity to the surface, they are often referred to in London as ‘the sub-surface lines’.

The second type of tunnel is the deep-level ‘tube’ tunnel. This method of construction was adopted to overcome the huge surface disruption caused by the cut-and-cover method and it took advantage of the blue clay soil upon which London is built. Single-track, circular tunnels of about 3.4m diameter (11ft 8in) were bored at a level deep enough to reduce conflicts with water mains, sewers and other underground services. Tunnels bored since the 1930s were built to a standard 12ft (3.7m) internal diameter on straight track and widened slightly for curves.

Cross-section of C&SLR tube tunnel showing the profile of the locomotive and passenger car. The tunnels were excavated with a shield and lined with cast-iron segments to form a protective ring. The internal diameter of the original tunnels varied between 10ft 2in (310cm) and 10ft 6in (320cm) but it was increased to 11ft 6in (350cm) on the Moorgate extension. A tube line required two separate tunnels: one for each direction of running. The older, sub-surface tunnels were usually double track.

Stations usually used a large single-track tunnel for each platform. Station tunnels are generally 21–25ft (6.4–7.6m) in diameter. The greater depth of these lines (an average of 66ft or 20m) meant that lifts or escalators had to be provided for street access. The technology of deep-level tube construction was available quite early on in the development of railways but it had to await a practical means of propulsion that did not require the use of smoke and steam. At first, cable drive was considered for London’s first tube line, the City & South London Railway (C&SLR), but this was soon discarded in favour of electric traction.

CITY & SOUTH LONDON RAILWAY (C&SLR)

The C&SLR was London’s first tube railway. It was opened in 1890 between King William Street in the City of London (near the Monument) and Stockwell. It used small, four-wheeled, electric locomotives hauling a set of three passenger coaches. The original, single-track, running tunnels were only 10ft 2in (6.6m) in diameter. Intermediate station tunnels were 20ft (6m) in diameter. Later tube lines were built to slightly larger dimensions.

Scale drawing of early C&SLR locomotive showing the principal parts. One feature introduced at this time was the location of the brake pipe connection hose at roof level. The small-bore tunnel restricted the height of the vehicle and there wasn’t room for anything other than the link and pin coupler below floor level. The lowest floor level was only 30in (762mm) above rail level. It had to be raised in two steps to clear the motors. The main body structure was only 10ft (3,048mm) long. Another unusual feature was the setting of the conductor rail height below that of the running rails. It meant that wooden ramps had to be inserted at points and crossings so that the collector shoes could ride up over the running rails.

The electrical equipment of the C&SLR, including the motors and controls for the locomotives, was contracted to Mather & Platt of Manchester. The locomotive bodies were built by Beyer Peacock, who were actually better known for their steam locomotives. The C&SLR locomotives’ equipment consisted of two electric motors, controlled through a hand-operated, rotary power controller carrying traction current through exposed, live contacts connected to the controlling resistors and motors. The original controller handle rotated in the vertical plane but later locomotives had enclosed controllers with the handle arranged in the horizontal plane, like a tramcar controller. There was no driver’s safety device (deadman’s handle) – it was to be another ten years before it was invented. In any case, a second man was available who rode in the cab to assist with coupling and uncoupling.

These locomotives were tiny. With a 10ft-long body (just over 3m), they were shorter than the distance between two sets of doors on a modern tube car but they had enough power, just, at 100hp (75kW) to haul a set of three trailer cars.

For train lighting on the C&SLR, a simple two-core cable was provided down the train at roof level and was connected to three lamps in each car. Connections between cars were along the roof, with sockets and a jumper cable between vehicles. The brake control pipe (later known as the train line) was also connected at roof level. The lights were fed directly off the DC traction supply and would reduce to a dull red glow when the line voltage dropped on uphill gradients or at busy times.

THE WATERLOO & CITY (W&C)

The next electric railway to be opened in London was the Waterloo & City Railway (W&C). I have to include it in this story, first because it is now part of the London Underground empire, although it was in main-line ownership for almost 100 years and second, because it had three major technical distinctions: it was the first tube railway to be allowed cables carrying motor current between cars; it was the first to adopt the duplex floor configuration for its cars, which became a standard for London Underground for the next forty years; and it was the first to be built to the American standards adopted on most of the new electric fleets built for the Underground’s electrification.

The W&C was opened in 1898 by the London & South Western Railway as a means of getting their incoming business passengers from their terminus at Waterloo to ‘Bank’ in the City of London. There were no intermediate stations, just the two termini. It was built with single-track tube tunnels like the C&SLR but with a 12ft 1½in (3.7m) internal diameter. The line was electrified at 500V DC, using a centrally positioned third rail. The larger tunnel allowed the third rail to fit centrally under the vehicle couplers instead of being located off-centre as it was on the C&SLR. The voltage was upgraded to 600V in 1917.

A sketch of a W&C motor car, showing the general layout and split-floor arrangement. The floor level was raised over the motor bogie to provide room for the traction motors. The trailer wheels were designed to protrude through openings in the floor, which were covered by seats. This was the first example of what became the standard...