On 22 Dec, 13:46, "Paul Scott" wrote:

I noticed on Clive's line guides, that after the last closure, the power
supply was made switchable between third or fourth rail mode. Which seems to
be another reason to question the length of closure.


I'm somewhat surprised at that; AFAIK (and I used to draw the power
supply diagrams which the controller used) the ELL was no different
from any other tube line. It wouldn't be the first inaccuracy from
Clive when it comes to detail (and in the rail industry, the devil
really is the detail).

Certainly the signalling was not compatible with a third rail power
supply.