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London Underground Completes Extensive Station at Piccadilly Circus (1929)

From nycsubway.org

Electric Railway Journal · Vol. 73, No. 11 · March 16, 1929 · pp. 439-440.

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The latest tube station to be opened in London is at Piccadilly Circus, a congested traffic center. Four years were required in its construction and its cost was about $2,500,000.

London Underground Completes Extensive Station at Piccadilly Circus. It serves two tubes and has a capacity of 50,000,000 passengers a year. All excavation and construction material had to be conducted through one 18-ft. shaft.

London's new and extensive underground passenger station has just been completed at Piccadilly Circus at the junction of two tubes, the Piccadilly tube and the Bakerloo tube. The original station at this junction dates from 1906, when the two tubes which cross each other at this point were opened. At the time it was built, this station seemed adequate to meet the requirements for many years to come, as it had to deal at that time with an annual traffic of only 1,500,000 passengers. Since then Piccadilly Circus has become a busy commercial center, being close to the retail shopping and theater districts of London. In consequence, the traffic at this station has grown until 25,000,000 passengers now pass through its portals annually.

When it became evident ten years ago that the old station was becoming inadequate, the new one was planned, and the last four years have been devoted to its construction. The public opening took place on Dec. 10, 1928, with appropriate ceremonies and was attended by a large gathering of distinguished guests. The cost of the new station was more than GBP 500,000 ($2.500,000).

It connects the Piccadilly tube, 102 ft. below the ground, with the Bakerloo tube, 86 ft. below the ground, and it provides entrance and exit to the platforms of both tubes by passageways and escalators. Owing to the necessity of keeping obstructions on the streets at a minimum during the work of construction and thus permit a constant movement of traffic, the engineering problems were complicated. An important factor in making them so was the need also not to disturb the services supplied by the gas, electric light, telephone, water and hydraulic power mains running in all directions immediately below the roadway. To complicate the problem further, a large sewer passed directly through the projected location of the main ticket office.

After the engineering drawings had been prepared, the custom was followed, as has been done with previous new underground stations, of preparing full sized models of the various levels so as to experiment with them and thus obtain the most satisfactory arrangement. In the case of this station, the models were built up with scaffold poles, cardboard and other pliable material, and the layout was arranged and rearranged and submitted to various tests until finally the most suitable scheme with respect to the position of escalators, landings, passageways and other features was produced. These tests were carried on at a place where covered accommodation was available for setting up a full sized plan of the main ticket office.

When work was actually begun on construction, excavation was conducted through a small "island" near the center of the area on which a monument stood. This was removed for safekeeping, and a shaft, 18 ft. in diameter and 92 ft. in depth, was sunk at this point. Through this shaft, the construction of all of the work with the exception of the main entrance and ticket office was carried out. This shaft was also used for the passage of materials, equipment, etc., to and from the work and for bringing spoil up to the surface. Fortunately the subsoil was suited to make construction fairly easy. It consisted largely of clay, with an overlay of gravel near the surface. Water was not, therefore, encountered to any extent, so that it was not necessary to build coffer dams or to work in compressed air.

After the shaft was sunk, the next procedure was to drive headings or tunnels at various depths. Before actual work could be begun on the station and its passageways, however, a special subway had to be built to carry the water, electric light and other mains which underran this area. This pipe subway is 12 ft. in diameter, or 3 in. larger than the railway tubes. It is of similar design, being of circular section and lined with cast-iron segments. Herein it differs from pipe subways constructed elsewhere in London, as they have been of square or arched section and brick built. This pipe subway extends around the Circus at a depth of from 18 to 30 ft. below the surface, and forms a sort of outer circle to the station. It is 550 ft. in length, but instead of being level throughout its course, it has frequent undulations, so that it may pass above or below obstructions that lie in the path. Inclined tunnels having a total length of 300 ft. lead from this subway to the streets around it.

When the pipe subway was finished, the various conduits, cables, etc., were placed in it. They are now quite readily accessible, and henceforth any work concerned with them can be conducted without the former necessity of opening the roadway and hindering traffic.

The most difficult part of the work was the construction of the main ticket office, as none of the streets overhead could be blocked or opened up while the work was proceeding. This task was achieved by a series of methodical burrowings, until the ground below the surface became a labyrinth of steel roofed and steel supported tunnels. Then, through the removal of the intermediate walls of earth, an elliptical chamber, 155x144 ft. in area and 9 ft. in height, was opened up only a few feet below the surface. The permanent steel work was then put in place.

Each of the four columns erected in the central portion of this floor is capable of supporting a weight 309 tons, while the 60 columns erected in a double row around the perimeter of the hall are capable of supporting individual loads ranging from 78 to 150 tons.

The six subways that radiate from this main entrance and ticket office were excavated by a similar method. Headings were driven from the main room along the sites of the subway sidewalls. and in these the foundations were built and the subways gradually completed. These subways connect the main ticket office and the various exits and entrances at the different corners. Incidentally, these passageways are arranged so that pedestrians can use them in crossing from one corner to another without buying a railroad ticket. Hence, the station is a public convenience also.

Owing to the depth of the platforms below the surface of the street, it was necessary to divide the escalators into upper and lower flights. In all there are eleven escalators, the greatest number in any London underground station, and the five in the upper flights are the largest number yet installed side by side. All have a speed of 100 ft. per minute.

An average of about 150 men were constantly engaged during the four years that were occupied in the construction of the station and its appurtenant work.

The greater part of the main ticket office is finished in travertin marble and presents a handsome appearance. The flooring is of large white tiles, each 1 ft. square. The decorations include some paintings in oil along the inner side of the headwall of the escalators. The central compartment contains a map of the world, showing the British Empire in a distinctive color. Backing this map are smaller panels with pictures representing the activities of the Underground in the sphere of urban and suburban transport.

The tiling of the public subways is of biscuit color, relieved by black borders. The lighting is by lamps of opal shade.

Following the recent practice of the company, a large part of the ticket sales will be by automatic machines. The latest types are arranged to print the tickets as well as deliver them. Twenty-six of these machines are arranged around the ticket office. As the zone system is used, they issue tickets ranging from 1 penny to 6 pence in denomination. There is also an automatic changemaking machine.

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This large circulating area is only 2 ft. underneath one of the busiest traffic centers in London.

Sources

Electric Railway Journal, McGraw Hill Company, Digitized by Microsoft, Americana Collection, archive.org.









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