On Mar 6, 6:14*pm, D DB 90001 wrote:

I agree that it would be costly, but not as costly as a new circle line. .. . . .

In addition, building a new line would require a lot of new stations,

Agreed all this would be very expensive and disruptive. Removal of all
the flat junctions on the existing Circle is just not practical, nor
do I believe it is necessary. Some selective work might be worthwhile
however. When I worked in London and used the line regularly, the
Junction at Baker Street often seemed particularly difficult to
manage. Lack of capacity at the Aldgate terminus seemed to force
immediate turnback of Metropolitan trains arriving there, resulting in
convoys of met trains waiting on the westbound at Baker Street to
access platform 2 whilst platform 6 remained resolutely empty for
extended periods of time as various H&Cs & Circles sat patiently at
the back of the queue. This might be addressed by a larger terminal
for the met, allowing better ordering and regulation of the westbound
flow, and with the demise of Thameslink to Moorgate I believe this
opportunity has now arisen to establish such a station at Moorgate.
The flat junction conflict at Baker Street is perhaps less of a
problem in the sense that there is potential eastbound Circle/H&C path
across the junction behind each of these westbound mets, but each
train approaching from Edgware Rd is severely limited in approach
speed because of the short overlap distance at the end of platform 5,
and this impacts capacity. A grade separation here could improve
matters for both the H&C & Circle lines.

Anyway purely for my own interest I've drawn up some of these ideas,
and any constructive comments from the group would be most welcome!

See my proposals here -

http://www.townend.me/files/circlenorth.pdf

--
Mark