In message , at 07:52:21 on Wed, 24 Jun
2015, Basil Jet remarked:
In my book the absence of the Northern Line City branch is more surprising.
I know the City is still pretty dead outside office hours, but Old Street
and London Bridge?

Perhaps because of the looming rebuilding of Bank station, with a new
southbound platform tunnel for the Northern line?

That wouldn't stop them running northbound service via Bank and two-way
service via Charing Cross, would it?

Assuming they can cut the power off the two tracks independently. But
they probably need the northbound track for engineering trains to
service the works happening on the southern tracks
--
Roland Perry