"Jack Taylor" wrote

The main problem at Moorgate is that to turn back an eastbound service
requires fouling both through lines to get the train into the terminating
bay and then the westbound again when it leaves. At various other
locations (Tower Hill, Mansion House) the turnback is between the two
running lines, reducing conflicts. This could be achieved at Moorgate, by
realigning where the westbound dog-legs into platform 2, taking it into
platform 3 (currently a bay) and making platforms 2/3 an island, with 2
becoming the turnback - there's rarely a need for both bays to be used and
4 would still be available in severe situations. This would need the
removal of the subway access from platform 1 and relocation of it - but,
compared to the other solutions, ought to be *relatively* easier to
achieve.

Turnback at Moorgate only happens during disruptions, and you've identified
the demand from Aldgate and Liverpool Street which means it would be
undesirable to turn back some or all Aldgate trains at Moorgate. So does
turnback at Moorgate happen often enough to justify investment? If it does
your idea would be worthwhile, though why not divert the WB into platform 4,
leaving 2 and 3 for turnback? It would also be possible to use the Up
Thameslink line as the WB Circle, etc, with the existing WB used for trains
starting back from Moorgate. This would avoid delays as occur at Tower Hill,
when the turnback train has been given the road, but isn't actually ready.
Meanwhile a through train is held waiting a path. All WB trains would be
either side of an island at Barbican.

Peter