SOME TIME in March London will be placed in possession of a third underground electric railway. The Central London, which is now nearing completion, will be the largest line of its kind. It has involved some remarkable engineering works, particularly in the construction of the Bank Subway, which has been partially open to the public for some weeks. The new railway does not aspire to be a trunk line, but merely a line for Londoners, supplying a rapid shuttlecock service between main centres. It is only six and a half miles in length, contrasting with about sixty and about twenty miles for the Metropolitan and District Railways.
Municipal Control for the Subway.
The Bank Subway is to be under municipal control to some extent. The Central London Railway Company is, of course, the sole owner, but
the City Corporation has a voice in the management ; it is responsible for
preserving order in the place, and has arranged to have a constable always on
duty while the subway remains open. The City also reserves the right to close all
the stairways except the two main ones at the Royal Exchange on all such
occasions as Lord Mayor's Shows and Royal visits, in order to prevent accidents.
It may be remembered that the condition on which the company was allowed to put
its booking hall and station under the road in front of the Exchange was that
the subway should be available to the general public, so as to avoid the
dangerous street crossings at this point. The Bank
will be the City terminus when the line is opened, not Liverpool-street, as was originally planned. Some
difficulty has arisen
in connection with the section between the Bank and Liverpool-street, so this
portion of the line will be delayed possibly for several years. From the Bank to
the western terminus at Shepherd's Bush there are eleven stations, all on the
main thoroughfares. From the City the stations, which lie some half a mile
apart, run as follows:- General Post Office, Chancery-lane, British Museum,
Tottenham-court-road, Oxford-circus, Bond-street, Marble Arch, Lancaster Gate,
Queen's-road, Notting-hill Gate, and Holland Park. Another half-mile run brings
one to the terminus at Shepherd's Bush.
Trains are to succeed each other every two or three minutes, so that there will be no time-table to consider, and practically no waiting for a train. The whole journey is to be performed in about twenty-five minutes, and from Oxford-circus to the Bank in about ten minutes, including stoppages. This speed, though about thirty per cent. higher than on the existing underground railways, is subject to improvement in the future, as the motors will be able to draw the trains at a much quicker rate. The average time occupied by omnibuses has been found to be one hour and a quarter for the whole distance, this being then average of 274 omnibus journeys recorded on behalf of the company. The trains are to be worked from a generating station situated aboveground at Shepherd's Bush, adjacent to the London and North-Western Company's coal depot, whereby exceptional facilities for coal supply will be afforded.
The stations will be approached by rapidly-running lifts, as well as by staircases - the latter for energetic people who prefer exercise to comfort; but experience gained in the United States and on the South London Railway shows that ninety-nine passengers out of every hundred elect to travel up and down by the easier method. At the Mersey the terminus lifts carried about ten million people in one year without either delay or accident. It is intended to have the lifts of the Central London constantly running, so that passengers may not be kept waiting.
The up and down traffic will travel in two separate tunnels, sufficiently deep to steer clear of all sewers and pipes, and to pass through the clay which underlies London. When Robert Stephenson pierced Primrose Hill for what is now the London and North-Western, it was considered more arduous to tunnel through that clay ,than through the stone itself - but now, owing to the Greathead Shield system, it has become a material eminently suitable for cheap and rapid tunnelling.
With one exception of a stretch of ground below High Holborn, where the Reading beds were encountered, the whole of the excavations for the tunnels have been made through the London clay. Compressed air was chiefly required when the tunnelling was proceeding through the Holborn Valley, below the bed of the old Fleet Ditch. The tunnels vary in depth. While the Bank station is only 60ft. below the roadway, Ox ford- circus station is 80ft. down, and Notting-hill Gate station 96ft. By way of helping to start and stop the trains, there is a gradient in the up tunnel of 1 in 60 for about 600ft. and a fall of 1 in 30 for about 300ft. in the down tunnels at each station. The stations stand, therefore, about 10ft, higher than the main level of the line.
The trains running in one direction only in each tunnel drive the air out, and draw fresh air down the station shafts. It has been calculated that the passing of one steam locomotive in a tunnel vitiates the atmosphere to the same extent as the passage of 30,000 people. Another advantage from having two tunnels is safety from collision. Noise will be deadened by giving a perfectly smooth surface to the interior of the tunnel. A well-constructed road-bed, laid with rails of the unusual weight of 100lb. to the yard, will contribute to diminish vibration and ensure steady running.
The tunnels will be much larger than on the City and South London Railway, the diameter being 11ft. 6in. as against 10ft. 6in., and the area therefore about one-fifth larger, and the carriages used will be wider and higher than on ordinary railways. Each train will consist of seven carriages, seating in all 336 passengers, or more than three times as many as on the South London. The carriages will have gangways running the whole length, and the doorways will be at the ends and not at the sides; they will be of the most improved and comfortable type, and well lighted by electricity, so that one may read in them as by daylight. The stations will also be brilliantly lighted with the electric light.
Municipal Journal, established as "London", February 9, 1900