That would be ludicrously expensive - again, they had that idea at the Boring Company, and it hinged on finding cheaper ways of building tunnels (beyond just ma

That would be ludicrously expensive - again, they had that idea at the Boring Company, and it hinged on finding cheaper ways of building tunnels (beyond just making them too small to fit emergency egress). As we've already seen, that never came to be, tunnelling is pretty optimised as it is. With your 100 tunnels you could probably just reach the capacity of the Elizabeth Line (again, just one example) but at 75x the cost...