Really? The Cross rail project in London cost only 2bn more than the Swiss project but does exactly that, create an entirely new line under the whole of London, which is ridiculously hard to dig under (or so I've heard). Why the hell does it cost $50bn for you?
Cross-rail runs mostly on existing lines. Only 13 miles of the 85 total are new tunnels, so cost per mile is still almost a billion dollars.
(Being a bit unfair here, because the tunnelling cost is probably less than half the cost - the other half being rebuilding half a dozen massive underground train stations while keeping them operational.)
Where did you read that? The project site says they have created 26 miles of new tunnels, also wider ones than ever before (6.2m). As well as 10 new stations. And all of this is slap bang in the middle of Europe's biggest city, which is pretty damn poorly laid out and not exactly conducive to huge scale construction projects.
True, but it's not like building a dual carriageway where it's essentially one road split in two, it's two independent tunnels running mostly in parallel. I'd wager that's more than twice as hard to do.
