asdf wrote:
Now add in say 6tph Hammersmith-Aldgate. This restores the frequency
on all routes to present levels, except it doubles the frequency on
the Hammersmith branch. This is, of course, good. However, Praed St Jn
is now hopelessly congested.

What am I missing here?

Two possibilities:
- Hammermsith to Aldgate is a transitional stage before the T-Cup is
introduced
- Hammermsith to Aldgate will be an extension of the T-Cup service (ie
trains will do a lap of the circle before terminating)

U