"Basil Jet" wrote:
[snip]
The Big Tube ends at Drayton Park (the road).
The Canonbury Curve tunnel ends near Ronalds Road. This is quite clear
from the satellite photos in the map resource of your choice. The
Canonbury Curve is significantly higher than the Moorgate Line at Drayton
Park station, I think high enough to bridge over the Moorgate Line in the
station, although the bridging actually occurs north of the station.
Whenever I have ended up in Drayton Park station for ten minutes there has
always been a train passing on the curve, so it got more use than people
seem to think, although I have not been there in the last five years.

West Anglia trains used to be serviced and stabled at Hornsey depot (the
result I think of the WAGN TOC 'grouping' of the WA and GN), and so used the
Canonbury Curve and Graham Road Curve to get to and from the depot to their
operating patch on the West Anglia lines out of Liverpool Street (ECS moves
for the peaktime extras meant stock used this connection during the day
too). This arrangement came to an end a while back - just as well because
the NLL upgrade required the (temporary) severance of this route.