A geographic map of the line looks something like this. The Northern spurs of the line merge at Camden Town and then split into two branches, one via Charing Cross and the other via Bank, before merging again at Kennington and heading towards the Southern terminus at Morden.
But anyone who’s travelled on the Northern Line will probably also be familiar with the line being colloquially referred to as The Misery Line. The line is old with the first stations opening in 1867; signal failures and delays are constant companions, despite TfL’s program of upgrades and modernisation. Splitting the line into two sections, with Charing Cross trains terminating at Kennington and Bank trans running through to Morden doesn’t seem to help much. Maybe it’s time for a new map of the Northern Line that reflects the reality of commuting on this line? Maybe that map might look something like this?