Around Highbury and Islington there are two short sections of disused tunnel on the Northern City Line, a consequence of the Victoria Line construction.
I've glimpsed the disused tunnel north of the station from the window of a Class 717, but I've never seen anything to suggest the disused southern tunnel still exists. Does anyone know if this is still extant?
Many moons ago I remember stumbling across an urban exploration website where they managed to visit disused sections of the NCL (among other hideously illegal visits to parts of the Underground!!!), which appears to have disappeared from the interwebs now. I can't remember if they got as far as Highbury on their clandestine travels.
yes but the Victoria Line had caused the NCL to lose its platforms at Finsbury Park, so this 'sort of' compensated for the loss.
The real wonder is that in a very welcome but uncharacteristic act of forward thinking the diversion of the NCL was actually built to allow full size trains - this was at a time when only small profile tube trains served the route. Maybe the decision-makers were feeling unwell that day...
I looked upon the Northern City Line as the city branch of the Victoria Line. Gave a new route to the city from the north-east.
The first trains to run in the future Victoria Line tunnel were of standard stock from the Northern City Line, tested north of Finsbury Park in experimental tunnels.
The Victoria Line trains came close to operating the Northern City Line service in 4-car formations via the old running line from Finsbury Park to Drayton Park. Whilst there were sufficient new trains to cover a Brixton service, not due to open for three years, the 1938 stock were required to boost other lines where compressor shortages led to 6-car operation. The plan came to grief when it was decided that the odd Victoria Line control handle, provided for shunt moves on the auto-drive line, could not be used to drive all day. It had to be lifted and turned whilst a vigilance button was held down. Fitment of new controllers, developed for the new C69 stock, was considered but the compressor shortage might be over before that could be achieved. This story was detailed in an old Underground News issue (Underground News November 2000 - does not mention the transfer route!).
Approaching H&I from the south, you can definitely tell where the tunnel widens at the step-plate junction but I'm not sure whether it's possible to see into the old tunnel or if it was blocked off at that end.