On 22 Sep, 12:40, David Hansen
wrote:

It does sound like it. The Prohibition Notice [1]
http://www.rail-reg.gov.uk/upload/pdf/prohibition-notice-tubelines-16...
seems like a sensible response to this by the RI. I find it
difficult to believe that anyone considered this a safe system of
work, particularly on what is ISTR a considerable gradient.

Arhcway station is in tunnel, as are the platforms at Highgate which
are still in use. The tracks come to the surface just South of East
Finchley station. The centre tracks at East Finchley used to lead to
the 'high-level' surface platforms at Highgate, and eventually,
Finsbury Park. They now just lead to Park Junction, from where trains
can reach the sidings which were alonside the Alexandra Palace
branch. Alexandra Palace is one of the highest points in london, and
it is not far from East Finchley. The ground level rises between
Archway and East Finchley, and since the tracks rise from underground
to the surface in this section they must be on a steeper gradient. I
assume that the intention once it reached East Finchley was to either
reverse the RGT down the centre tracks, and then reverse again into
the sidings, or just leave the train in one of the centre platforms
until it could be recovered later in the day.

As I understand it, the RGT was being hauled North on the wrong, i.e.
Southbound, line, so that when it ran away it was at least in the
right direction; things could have been even worse if it was being
hauled on the Northbound line.