So they're halfway through digging the tunnel, not halfway through doing all the other things to make the tunnel actually as useful as musk is claiming.
This all just seems like subways from first principles but probably worse.
This all just seems like subways from first principles but probably worse.
But nobody wants to be the one who signs off on "long sections of major roads closed for months at a time over a period of several years".
Sure you can. I ride such a line every week day.
True about the most direct route, but having uncontested right of way tends to make a big difference in travel times. And in grid layouts, where you want to go is closely aligned to how you get there.
The big advantage is creating tunnels with a smaller diameter, allowing them to dig much quicker. So much space is wasted between each subway car that a large diameter isn't necessary.
I think putting cars in these tunnels is silly and that subways are obviously the best answer personally, but I'm also watching two new light rail lines being put in next to my house. It does not seem quick (though they're elevated). It'd be lovely if those tracks were somehow underground faster and cheaper than above ground.
I'm happy enough it's finally happening, but if it could be done economically in a way that reclaimed the land the rail lines are on to make a park or more housing? And without trains driving by my windows on both sides? Maybe the boring machine itself is somehow better than what we dig tunnels now.
In SF, they spent years surveying, moving utilities, excavating stations, etc., dug the actual tunnel in (IIRC) a year, and have spent subsequent years finishing all of the other stuff that makes it more than a hole in the ground.
[*] About their property values
Maybe the whole thing could have been done in half the time without public meetings, but that’s neither here nor there. The work of moving utilities and keeping sinkholes from forming in downtown SF is still incredibly complex, and seems to me to make up the bulk of the schedule.
Don't believe the hype that this is "under a city." It's under a bunch of parking lots, which have little to zero underground utilities or other infrastructure.
It's not like they're burrowing under New York. But it might be good practice.
And we understandably should be wary of any innovation in processes.
Because often it is just cutting corners for safety and reliability.
Even if you had ideal conditions or an amazing new TBM that goes through any material, you're still dealing with a machine that scrapes at rocks for miles on end. The parts that do the digging need constant replacement, underground, on the inconvenient side of the boring machine, and even if you did the actual digging faster that'd mean repairing it even more often.
I think the only time it's moving close to high-rises again is over by the University.
Edit: I believe they went so deep because of the volume of glacial deposits in this area. Otherwise they would have been going through gravel. That made building the stations a bit of a pain (the Beacon Hill station still has chronic problems with water. It smelled like a moldy towel for a long time).
He’s trying to parlay his life’s work into civilization on Mars. Everything he’s investing time and energy into has uses here, today, but the prize he has his eye on is not here.
Does making a tunnel boring machine lighter or smaller have advantages? Sure, if the machines get used to dig more than one tunnel then a more portable design will begin to develop. But nobody is worried about paying well over $1000/lbs to move the damn thing. And nobody is worried about how big a parachute you need to land it in Martian atmosphere without breaking it.
Knowing Musk, he isn’t spending time on this plan if it does nothing for his dream. Therefore there’s a connection. What might that be? What would digging large holes have to do with sending people to an environment with barely any atmosphere and massive sandstorms? Oh.
I expect solving that problem will take ages. If he starts now he might have some major progress by the time he’s gotten a few missions to Mars. By the time habitat management is a problem he may have something that is pretty crazy but not insane.
I also expect that when spending another $1000/lbs on cutting surfaces represents a net savings, you’ll see him working with some pretty bizarre and exotic materials. What that would be will come as a surprise to me, since I haven’t paid any attention to materials science since about the time they started making synthetic diamond.
Or maybe tunneling speed simply isn't the bottleneck so no one ever tried going faster. If it takes 3 months to dig out the tunnel but 6 months to fit it out then you've gained nothing.