"Colin McKenzie" wrote

Hmm. From a state of ignorance:
- how hard would it be to quadruple to Neasden?
I know there's spare space between the platforms at Wembley Stadium,
and IMO the potential traffic would justify quadrupling at least to
West Ruislip, if not to High Wycombe.
- are the two extra Marylebone platforms mentioned by Paul feasible?

I suspect that the easiest way to increase capacity on the Chiltern Met Line
would be to extend platforms to allow 8 coach trains. If capacity for more
trains into Central London from the Joint Line is needed then Old Oak to
Northolt Junction should be redoubled and the linespeed brought back to
90/100 mph. There should be platform capacity at Paddington when Crossrail
opens, and there are tentative plans for additional platforms if needed.

Marylebone of course has two extra platforms already, but I don't think
there is scope for any more.

Peter