[asdff]

As dramatic as line closures are, the impact to commuters can be minimized if the transit agency supplies shuttlebusses servicing the line in its place. When LA metro closed substantial sections of the Expo and Blue lines a few years ago, the shuttle routing only added a few extra minutes to commuters trips along those corridors.

[gsnedders]

You need 187 buses per hour to have the same capacity as the Piccadilly Line has on-peak (using the capacity of the New Routemaster), or, alternatively, three buses per minute. It's hard to imagine any way in which that is practically workable. I think the most frequent bus service in London currently is scheduled for 30 buses per hour, by way of comparison.

Add to this the fact that average road speed in Central London is about a third of average Underground speed, hence you're quite possibly looking at making journeys three times as long, even ignoring the extra congestion that all those buses would cause.

[ddek]

Nice idea, but no chance it works in London. It’s faster for me to go the long way round the northern than anything overground, even a taxi.

[andrewaylett]

Unfortunately, that's unlikely to work in London where there are already more people on public transport than private transport [0]. The London Underground has roughly twice the overall capacity of the London Bus network [1].

[0]: Specifically inner London, ref Page 67 of https://content.tfl.gov.uk/travel-in-london-report-13.pdf

[1]: By spaces-times-distance, ref Page 101 ibid.