[OT] London Underground Trains

My favourite 'Drain' event was standing next to a lady with an opened bottle of wine; most people seemed to be avoiding her. Conversationally, she said2 I just off on holiday via Stanstead and found I had this part used bottle in my fridge - far to good to throw awaym so I decided to bringb it with me." as she took her seat she delved into her bag and took out a wine glass and poured some.

How lovely; that is how life should be experienced!

Ah! That explains why people who end up sheltering in the centre well are not at risk of electrocution.

I tend to agree. However, wasn't it a female cabinet minister who, not so long ago, got taken to task for drinking a can of supermarket "gin and tonic" on a tube (in breach of the no drinking rule).

The outer power rail is +420V, the inner power rail is -210V, so not recommended

In those circumstances they bond the centre rail with the running rails and supply something like +690V to the outside rail as the best compromise. (Suburban trains are fed with +750V to the outside rail; the Underground has +420V to the outside rail and -210V to the centre, making 630V total. All voltages are "nominal", so there will be a tolerance either way.)

You sure that's still the case in stations? In any case I'd prolly take the risk if the alternative is being chewed up by the gubbins under the train.

I should think so. They used vacuum brakes one time, which made them inherently fail safe if the connection between the carriages was broken. With air brakes a reservoir has to be maintained.

Even our mainline trains aren't big enough for true double deckers due to limited loading gauge of the bridges and tunnels.

They experimented with one-and-a-half deckers once:

I heard it said (on the recent Yesterday series about the Underground) that the pit is to prevent (or foil) suicides.

It is made easier as there is bound to be a space there due to the larger diameter tunnel sections needed for stations. I haven't seen anything like it on other lines.

There are two parallel wires that run along the side of the tunnel. When shorted they cut the power to the rails. It's how drivers make the line safe before evacuating passengers.

I thought (maybe without anything to base it on) that those were for the driver to croc-clip a telephone handset onto for emergency contact?

They may be dual purpose ?

I knew a few tube drivers and they said that's what they were used for.

Never been led to safety underground. It sounds like a laugh if you're young and dumb :) Much like evacuating an aircraft.

Less fun when you're 50+ ...

Sounds like it is/was both

I know that (under the old system) for normal UK lines, sections of track were isolated from the next and a low voltage across the rails, fed from one end, holding a relay closed at the other end. A train in the section shorted the rails together through its axles and released the relay, causing signals behind to show red and the line to be indicated as occupied. In the event of a fault (loss of power, broken connection or broken rail), the feed to the relay was lost and again red was shown.

If a train was derailed and might be too close to the parallel line, there was a lead in the guard's compartment to clip to those rails and force a red on that line too.

Whether the modern (and far more complicated) systems still work that way, I don't know.

There must be an equivalent for the underground.

Ah, I was right earlier, then! (if a little out of date)

They are bare also because a tepehone can be clipped on to them in emergencies (or used to).

Both.

East Putney. There is no West Putney.

I think in the old days the driver could clip a mike/headphone across those wires and talk to HQ. Perhaps he still can.