I think the first actually does happen already, if only at a smaller scale.<p>I know overground has some stations where the last car can&#x27;t fit on the platform. (Circle line might have couple of these too, if I remember correctly.) And I&#x27;ve noticed that a couple of fairly central stations have been closed for more than a year due to construction works.<p>So extending platforms a couple of stations at a time should be possible - one fully closed and another with just one end blocked off. It would take ages and insane amounts of money to do that for the entire line, you&#x27;re right about that. But maybe just for the stations where it would provide the biggest benefit?