TUBE RAILWAYS

Evening Post, Volume CXXVIII, Issue 103, 28 October 1939, Page 12

TUBE RAILWAYS

DANGER IN RAIDS

RIVER, MAINS, AND SEWERS

COSTLY SAFEGUARDS

(By Air Mail, from "The Post's" London Representative.) LONDON, October 6. Protection of the London Passenger Transport Board's railway and road service from air-raid damage is costing £1,000,000. The plan involves a vast programme of works at 50 underground stations, 19 of which are closed for the purpose. Sixteen giant floodgates are to be built in the tunnels of these lines running under the Thames. In other stations work has to be done to isolate flooding from burst -water mains and; sewers. On the Bakerloo Line four floodgates are installed at Charing Cross and two at. Waterloo. On the Northern Line two gates have been installed at Strand, and two at Waterloo. The line should be open in from six to eight weeks. Two gates have.still to be put in at the Bank, two at London Bridge, and two on the East London Line. One of the gates at Waterloo Station, at the end of the northbound platform on the Northern Line, was seen in action this week. It'is made of-built-up steel, 13in thick, ahd weighs nearly six tons. The gate slides horizontally into position within a frame of cast iron across the mouth of the tunnel. It can be worked either by hand or by electricity, and there, are alternative supplies of power, When closed the gate could resist a force of over 800 tons, which is several times'the greatest pressure of water that could bear on it. SAFETY PRECAUTIONS. When an air-raid warning "reaches the office of the traffic controller at Leicester Square Station, the signal "Close the doors" is sent to the operators, of whom there are always two on duty at each gate. The signal is acknowledged electrically from the operators* control cabins, in\ which there are illuminated diagrams showing whether the under-river sections of line are clear of trains or not. Interlocking gear makes it impossible to close the gates with a train between them. Before a gate can be closed the small gaps between the gate-sill and the rails are filled with shaped metal blocks, lined with rubber, so making a continuous runway for the gate. All possibilities are allowed for. A, train cannot be caught in a tunnel. Gates can be closed by hand in four and a half minutes if current fails. An escape hatch is so placed that normal routine examination- of the permanent way can continue if gates are closed. An ordinary kitchen tap looked almost out of place m the massive structure of the steel gate. It will be used to see if the underwater section of the tunnel is flooded. After the Munich crisis, London Transport's engineers made a survey of underground stations. Fifty stations . were found to need protective measures. At 31 of these, work could be done without disturbing traffic. At the remaining 19 work was more complex, and stations had to be closed temporarily. ■ "'.■■" At King's Cross every one of the subway entrances to the sub-surface ticket hall was threatened by the newness of sewers and water mains. At one point the floor of a subway was only six inches above the roof of one of the largest sewers in London. The four passages leading from the circular ing area had to be blocked up by insertion of bulkheads of concrete up to six feet thick. That is why, two days before the war, the station had to be closed.