Thanks, so no real risk to the public (or to staff as no-one is on track when trains are running!)
Funnily enough, prior to the ‘70’s modernisation shutdown, I spent 3 nights recording audio of trains in tunnels, sump pumps running and the wooden carriages rattling. Talking to the maintenance crew on a train after services ended for the night I asked if there was anything to see of the old cable days. They said there was, and we stopped between West Street and Shields Road - which was cut and cover under Scotland Street, by necessity a long straight section of both tunnels (we were on the Outer Circle).
Once stopped, we exited the front door down to the track, and there was a chamber that brought the cables down from the engine house above (then Howdens Engineering) and across to the Inner Circle also. To get to the chamber we had to step over the power rail, which was explained later as carrying the full traction current - the only advice was ‘don’t touch it’! I gather the voids were infilled as part of the 70’s modernisation scheme, so like the old Merkland Street station - nothing visible!