§ 57. Mr. Boyd-Carpenterasked the Minister of Transport whether, in view of the dangers to life and health which resulted from the breakdown of the 1527 London Underground on 6th July, he will make a statement about the cause of this occurrence and as to the steps being taken to prevent a repetition.
§ Mr. PeytonYes, Sir. As the statement is inevitably somewhat lengthy, I will, with permission, circulate it in the OFFICIAL REPORT.
§ Mr. Boyd-CarpenterDoes the statement contain an indication that my right hon. Friend is concerned to lay down that there should be an alternative supply of light to the trains and sufficient power to move them to the nearest station in the event of a repetition of the potentially very dangerous situation which existed on Monday of last week?
§ Mr. PeytonYes, Sir. I fully appreciate my right hon. Friend's concern. Perhaps I could just read to him one extract from the statement:
Detailed investigations are now being made by London Transport to see what further steps can be taken to avoid a recurrence of this serious power failure before modernisation is completed ….Following is the statement:Electrical power is supplied to the Underground by the London Transport power stations at Lots Road and Greenwich. Lots Road, which has recently been modernised, is the main station and it supplies power at 22,000 volts. Greenwich is at present undergoing modernisation and is temporarily working in two parts; old steam turbines, which are gradually being replaced, supply power at 11,000 volts and newly installed gas turbines supply at 22,000 volts. The distribution system from Greenwich is designed for 11,000 volts only, so the 22,000 volts supply has to be stepped down by transformers at the power station.Whilst the work of modernisation is going on at Greenwich the station cannot meet the maximum demands made on it at peak periods. It therefore draws power from Lots Road through a heavy underground cable that links the two stations. This cable is protected by circuit breakers, like giant fuses, that are set to operate if the current becomes too great.At 17.13 on Monday, 6th July a relay that operates the circuit breakers failed and the breakers cut off current in the heavy cable, although at this time the load was well below the maximum allowed. The immediate overload thus put on to the Greenwich station operated further protective circuit breakers within the station and power was cut off from a large part of the system supplied from Greenwich. This affected all the Underground lines except the Victoria Line, which is fed from Lots Road directly, and the Metropolitan line north of Baker Street, which is supplied from the Grid.1528In the case of most lines the traction current was lost only intermittently, or was restored after a short period, but power supplies to the signalling system and to the all-stations communications system operated from the London Transport headquarters were not fully restored until 19.30. The loss of the communication system led to rapid overloading of the internal telephone circuits and made the task of informing passengers of the situation extremely difficult.There were some 200,000 people on the Underground system at the time of the failure of whom some 30,000 were in trains seriously affected by the failure. Where traction current was available, but signals had failed, trains were moved with extreme caution to the nearest station. Where trains could not be moved the passengers were kept in them, except that the decision was taken to evacuate a number of trains, including three in deep tunnels. In these cases evacuation was done in an orderly manner and in accordance with laid down procedures. Although passengers must have suffered considerable discomfort because of the heat there was no general danger from electrical shock or lack of air. Although some passengers were overcome by the heat there have been no reports of injury or serious illness.The modernisation of power supplies to the Underground is being carried out in accordance with recommendations by three of the leading firms of electrical consultants in Britain. It was a task of considerable complexity to keep Lots Road functioning during the installation of new plant and the same problems are being tackled at Greenwich. It is believed that, when the modernisation of Greenwich is completed in 1972, there will be the most reliable possible system of electrical supply for the London Underground.Detailed investigations are now being made by London Transport to see what further steps can be taken to avoid a recurrence of this serious power failure before modernisation is completed and also what steps can be taken to Improve the reliability of the communications system in circumstances such as occurred.My inspecting officers are keeping in close touch with these investigations.