Fortunately, younger cities like London and Paris don't have the problem that ancient metropolises like San Francisco have, so they can build subway at a fraction of the cost of $4b/mi that SF needs to ensure that it's built right. There's a lot of history in California. Pretty unique in that regard.
To be honest, I like 280 without there being something on top of it, but if that's what's necessary to get a rail line down there I'd gladly accept it. Just the per-mile cost. Well, I'm not looking forward to paying more than half of every marginal dollar to the government so it can give it to its cronies who just happen to be husbands of famous California politicians.
I’m not sure they were at all implying that California was exceptional in that regard, to be fair, but at least that urban tunneling involves many costs besides the physical boring.
In any case, I wouldn’t use the UK as an example of tunneling efficiently. Crossrail, for instance, is on the order of more expensive urban US projects and there’s a fairly consistent recent history of either not building or letting existing rail infrastructure decay.
The funny thing is that Crossrail, the most humongously expensive UK rail project, is somehow a third the cost per mile as what SF quotes for its newest subway.
To be honest, I like 280 without there being something on top of it, but if that's what's necessary to get a rail line down there I'd gladly accept it. Just the per-mile cost. Well, I'm not looking forward to paying more than half of every marginal dollar to the government so it can give it to its cronies who just happen to be husbands of famous California politicians.