London Underground - Are the rails in a station always electrified?

When you look at the rails you will see 4 rails. 2 are the running rails 2 are power rails. The power rails carry 240-640 DC current. They are always "live" unless switched off,which doesnt always happen as is not always req. The power for any line is centrally controlled.

To switch off a section in a staion would require a lot of swiches and take a lot of time. The proceedure to isloalte a given area of track, i.e a yard takes about 40 mins to drop the power and then the same to reinstate it.

There are unfortunatly many incidense a year where people get killed by touching the live rails.

Think that through. Why would the railroad put in special switching circuits that turn on 3rd (or in the London underground, 3rd and 4th) rail power only when the train is in the station? They've fooled around with a somewhat similar idea with a streetcar system in France, and it's just not working very well.

You know, there's about one railway electrocution incident a year, and when the guy survives, the most common thing they say is "I thought the power was off". That's a case of convenient thinking. As in, well, it serves my interests better if I believe X, so I'll just believe it.

I would expect the power to be on 24x7, even if the railway has "shut down" hours. That's because first and last runs have to get out and in to the shop, deadhead moves between shops, and special service for late night events. Like the electric power to your house, it's "always there when you need it".

How are the dummies surviving? Well third rails are for powering trains, not electrocuting trespassers. There's some allowance for track workers, and that gives an allowance to the foolish and lucky. Not luck you want to push, though.

Do not confuse current and voltage...

Technically the rails do not carry electric *current* when there is no train drawing power from them. But the rails ARE powered all the time (except during maintenance works, of course) and the electric *voltage* in them is definitely dangerous! Current flows when there is an electric circuit, be it through the motors of a train or through a person...

The only railroad i know of where the live rails are powered only underneath the vehicle is the tramway of Bordeaux (France), that uses live rails in the street, which should not be powered permanently for obvious reasons...

Ask London Underground.