Insulated joints at Aldgate East

[edwin_m]

Noted about half way along the eastbound platform today.

Two new-looking insulated joints, about 3m apart in only one running rail. Cables are attached to the rails either side, leading to a large disconnection box on the platform wall, with a sign noting the end of a track circuit. But there are apparently no cables connecting to the piece of rail between the joints.

Any thoughts?

(there are also datum plates on the adjacent platform...)

 

[sharpley]

Think its just to isolate 2 track circuits, the rail between the 2 insulating joints just to provide the isolation (hence no cables). Been a while since I did my LUL track awareness course (1999) so happy to be corrected.

 

[Bald Rick]

Yep they are all over the (track circuited) LU network; double block joints. If one fails, it doesn’t fail the signalling. Of course there’s twice as much maintenance, but that’s a price worth paying on the busiest parts of the network.

 

[John Webb]

Yep they are all over the (track circuited) LU network; double block joints. If one fails, it doesn’t fail the signalling. Of course there’s twice as much maintenance, but that’s a price worth paying on the busiest parts of the network.

Is there a testing procedure to detect if one or the other of the two joints has failed so it can be sorted? Or do you wait until both fail and replace both?

 

[civ-eng-jim]

It should measure 3.3m between the insulatd block joints, or 10' 10" in old money.

 

[Bald Rick]

Is there a testing procedure to detect if one or the other of the two joints has failed so it can be sorted? Or do you wait until both fail and replace both?

The former I should hope! Mark One eyeball and a voltage meter I should think.