London Underground

[slp619420]

The London Underground runs on fourth rail but i wondering if there parts of the underground that runs on third rail like on the Isle of Wright?

It's just an idea i had in my head about a third rail underground

[phill70]

Not in London, as far as I know, Happens in Merseyside though.

However SR emu's can and do run on 4th rail lines.

[tubemad]

all the tube network is 4th Rail 750v DC. Mersey network is indeed 3rd rail, though mostly overground anyway.

The only underground network i can think of with 3rd rail in the UK is in Scotland, the Glasow Orange Clockwork (their underground system)


cheers,

James.

[Tonysmedley]

Using a 4th rail to carry the heavy return traction current instead of the running rails avoids complications with signalling. The Glasgow undergound is a particularly simple system with just two separate circles of track, connected by only two crossovers and with two other turnouts leadsing to the depot.
Signalling is therefore much simpler than at many London Underground junctions.

[BR7MT]

all the tube network is 4th Rail 750v DC. Mersey network is indeed 3rd rail, though mostly overground anyway.

The last time I checked, our network used 630V d.c. ...

Regards,

Dan

[tubemad]

Has it changed? I remember asking once and apparently they kept changing it between 660v and 730v, wouldn't surprise me if its changed again!


cheers,

James.

[phill70]

The SR 3rd rail network runs on 750vdc, but in the London area it drops to 630-660vdc, so I would imagine in contested area's everwhere else, it would be roughly the same.

[passedcleaner]

I believe SR units can run on a variety of voltages - the nominal voltage is 750V DC but in areas of high traffic / no substations it has a habit of dropping as low as 600V. LUL/SR joint routes such as the Euston-Watford line therefore are set for 630V DC, and the SR units running over it will experience a power drop accordingly.

Seb

[BR7MT]

As far as I know it has always been 630V d.c.

Regards,

Dan

[glasgowworks]

London Underground network are electricfied at 630v dc.

In the southern region, lines are electricfied after around 1958 are 750v dc, but lines electricfied before that time are 660vdc (including Isle of Wright), but they remain the same today.

[darren10000]

...before that time are 660vdc (including Isle of Wright), but they remain the same today...

Is that the Chinese Isle of Wright or the Uk Wight one

(Gets Coat and leaves!!!)

Darren
73E

[passedcleaner]

In the southern region, lines are electricfied after around 1958 are 750v dc, but lines electricfied before that time are 660vdc (including Isle of Wright), but they remain the same today.

Are you certain about this? I'd certainly never heard it before. Be interested to know your source.

Thanks

Seb

[ashgray]

I'd be interested to know where this "Isle of Wright" is that I'm reading about a few times in this thread....

Ash

[slp619420]

The Isle Of Wright i was on about was the one near Portsmouth that has the 1930's Tube Stock running on 3rd Rail

[Tonysmedley]

Ah! that line on the Isle of Wight!