Pipes - I mean 'cables'

[L&Y Robert]

Traveling on the tube the other day I noticed (again) all those “pipes” on the tunnel wall. (Yes, I know they’re not actually pipes, but cables. ‘Nothing to see out of the window on the tube except pipes’, my sister says). But I fell to wondering why there are always so many – even out in the country, at places like Amersham. The “real” railway used to get along quite well with half a dozen wires – sometimes fewer – stretched out from wooden pole to wooden pole on white pot insulators. Meanwhile the “Tube” has these thick cables, usually several at a time, hooked over special brackets on concrete posts all the way along. They even have special bridges over the line sometimes, just for the cables. What are they all doing?

 

[ilkestonian]

Would the Tube ones be related to the need to provide power to the tracks at regular intervals, whereas the old telegraph poles carried wires used for communication?

 

[Mojo]

Most locations will have a compressed air main; used for operating points, train stops and the like. Typically points on the Mainline are thrown by the use of electric point motors, whereas traditionally air is used on the Underground. Amongst the other cables will also be a leaky feeder for the radio system.

Also worth mentioning that most of the Mainline also has cables but these are carried in cable troughs in the cess.

 

[John Webb]

Besides heavy-duty power cables for traction current, many are multicore cables for communications and signalling in particular. In early days these would have probably been lead-sheathed to protect against the damp - more recent cables are plastic-covered but probably with steel wire armouring underneath as protection against physical damage.

I'm also uncertain to what degree LT bother to remove old cables when new ones have been put in place - so it's possible a number of the visible cables are no longer in use!

 

[bramling]

Besides heavy-duty power cables for traction current, many are multicore cables for communications and signalling in particular. In early days these would have probably been lead-sheathed to protect against the damp - more recent cables are plastic-covered but probably with steel wire armouring underneath as protection against physical damage.

I'm also uncertain to what degree LT bother to remove old cables when new ones have been put in place - so it's possible a number of the visible cables are no longer in use!

With regard to removing old cables, definitely quite a few redundant cables in many locations.

 

[edwin_m]

This has some relevance to cables on the Underground:

http://www.londonreconnections.com/2016/its-good-to-talk/

From telegraphs to telephones, cables to Connect, over its 150-year history the London Underground has remained at the forefront of communications technology. We look at the journey from a single telegram line to an integrated radio system that connects over 12,000 people making upwards of 11m calls a year, and ask what happens next.

 

[nidave]

A little (but not quite) OT
If you want a good read and have some time to spare check out this

Automatic Junction Working and the Programme Machine - it mentions the cables needed for train describers.
http://www.metadyne.co.uk/pdf_files/Automatic_Junction_Working.pdf