IMHO what the Circle Line desperately needs is some kind of relief
location where trains can be regulated.

4 tracks for Circle use *only* where you can do bifurcating operation
and/or recess trains and/or overtake if necessary are all contribute
positively to service regulation. ((The point about overtaking is
taking one train out of the flow when trains are bunched, re-inserting
it when the bunch has passed.))

Edgware Road is out of the frame these days since the broken Circle,
there is almost nowhere else where anything can be done.

Someone pointed out on some forum recently - here ? District Dave ? I
forget - that Kings Cross and Victoria are very busy stations with
long dwell times and oppurtunities - albeit expensive ones - have been
lost/impossible in recent/planned rebuild to put in 4 platforms. The
advantage cited was both locations are away from all the junctions,
and diametrically opposite each other, offering 2 regulation
locations. Clearly neither would happen now.

But if you slightly displaced the suggested regulation locations
clockwise around the Circle, you could use *Barbican* and South Ken.
The latter has I think room for 4 tracks still within the existing
structure/cutting, although it would need some shifting around of
trackside kit.

Thus a more sensible use of the redundant ''widened lines'' going east
of Farringdon would be to diverge from the Met-City to 4 platforms
through Barbican and converge back to 2 through lines through
Moorgate. I suggest there is enough space to do this but would need a
certain amount of significant work east of Barbican to achieve.

Ideally for bifurcating working you need an island for each direction
with both platform faces going the same way - neither South Ken nor
Barbican would offer this, so any trains being recessed or tipping out
would cause passenger to have to use crossways, but I suggest overall
this is an advantage : it train X is in the existing platform train Y
is stuck in tunnel behind. With 2 platform tracks, Y might get in
allowing passengers to cross to X while Y recesses. Overall it keep
passengers moving even if one train does not.

The whole point of this suggestion is to address the fundamental weak
point of the Circle - it has zero resilience. If you have 4 track
locations it allows sort of elasticity for the operators.

Far too subtle a point for uk.railway ''but we've always done it his
way'' die hards of course.

--
Nick