4 ms·

Yes, he claims to have found a way to drastically reduce construction consts. First of all, reducing the tunnel diameter, as the digging speed is constrained by

by _ph_ 6y ago

Yes, he claims to have found a way to drastically reduce construction consts. First of all, reducing the tunnel diameter, as the digging speed is constrained by volume. Second, he tries to improve the technology of tunnel boring machines. With the smaller tunnels, there is the requirement for smaller vehicles. You can't run standard trains through these tunnels. For now, he is using Teslas (quite obvious choice) to demonstrate the tunnels, but equally it is obvious, that to increase the capacity of tunnels, you want more bus or train-like vehicles. It is so funny how people critisizing Musk assume, he wouldn't understand so simple connections like seats per vehicle and transit density.

ashtonkem 6y ago
> It is so funny how people critisizing Musk assume, he wouldn't understand so simple connections like seats per vehicle and transit density. Well, he does keep showing renderings of public transit stations full of Teslas and not, you know, people. It's not really a big leap to say that he doesn't understand when he keeps marketing as if he doesn't understand.
- _ph_ 6y ago
  Sure he does. And he probably has a reason. But it is absurd to assume he hasn't considered that "trains" allow more people in shorter ties than a single car. So you can speculate why he does as he does, but you are talking about someone sending people to space.
welterde 6y ago
If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.
- ashtonkem 6y ago
  Ah, that is a very interesting detail. A compelling argument to stop with the whole “we’re going to zip around teslas” and just promise to make subways cheaper.
  - Robotbeat 6y ago
    The Boring Company And Musk said they’d be willing to make Subway tunnels, too. Turns out Teslas are cheaper per passenger seat than a subway car plus have less requirement for specialized infrastructure (rails, etc). So if TBC is gonna be doing the whole project, they intend to use Teslas. It’s not a bad engineering choice. With automation (not hard in a tunnel), can achieve similar throughput as a Subway.
    - welterde 6y ago
      There is no way you can get even close to the same capacity as a subway.. not even for a point to point setup. Minimum train space with pretty standard signaling can be as low as 90s. With modern moving block systems that can be pushed even lower. The tube trains have a seating capacity of around 250 people and 800 people can be standing. This gives a capacity of between 3 and 12 people per second. How are you going to inject 1 car per second (to reach the lower level) into the tunnel in a safe way? And even if you could do it - Consider how huge the stations must be. They have to contain 100+ cars plus space to enter/exit them (couple seconds to come to a stop, 10s of seconds to leave the vehicle - with some people quicker than others -, 10s of seconds for other people to enter the vehicle, couple seconds to accelerate and synchronize to the flow..).
      - Robotbeat 6y ago
        Cars on freeways already regularly do sub-2 second spacing. If each vehicle had 7-16 people (as TBC plans), you’d get similar to Subway capacity. Folks who dismiss getting subway-like throughputs haven’t actually done the math.
        welterde 6y ago
        The planned capacity is however only 4400 people per hour for the CES tunnel so about 14s spacing (some other projects even lower). One train every 90s has a capacity of more than 10000 people (and that's not even rush hour with any people standing). Sub-2 second spacing is quite unlikely to be used, since stopping distance (with 0 reaction time, which is not too unreasonable with LIDAR/RADAR) dictates around 2s spacing between vehicles (1.9s at 100km/h for teslas I believe). And while humans might be fine with ignoring safety aspects computers can't and shouldn't. Nevermind that building a subway-light vehicles (more similar to a people mover) is not really the same thing as using slightly-modified Teslas as subway replacement (which is what it seems they will be using for now)..

by _ph_ 6y ago

ashtonkem 6y ago

> It is so funny how people critisizing Musk assume, he wouldn't understand so simple connections like seats per vehicle and transit density. Well, he does keep showing renderings of public transit stations full of Teslas and not, you know, people. It's not really a big leap to say that he doesn't understand when he keeps marketing as if he doesn't understand.

_ph_ 6y ago
Sure he does. And he probably has a reason. But it is absurd to assume he hasn't considered that "trains" allow more people in shorter ties than a single car. So you can speculate why he does as he does, but you are talking about someone sending people to space.

welterde 6y ago

If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.

ashtonkem 6y ago
Ah, that is a very interesting detail. A compelling argument to stop with the whole “we’re going to zip around teslas” and just promise to make subways cheaper.
- Robotbeat 6y ago
  The Boring Company And Musk said they’d be willing to make Subway tunnels, too. Turns out Teslas are cheaper per passenger seat than a subway car plus have less requirement for specialized infrastructure (rails, etc). So if TBC is gonna be doing the whole project, they intend to use Teslas. It’s not a bad engineering choice. With automation (not hard in a tunnel), can achieve similar throughput as a Subway.
  - welterde 6y ago
    There is no way you can get even close to the same capacity as a subway.. not even for a point to point setup. Minimum train space with pretty standard signaling can be as low as 90s. With modern moving block systems that can be pushed even lower. The tube trains have a seating capacity of around 250 people and 800 people can be standing. This gives a capacity of between 3 and 12 people per second. How are you going to inject 1 car per second (to reach the lower level) into the tunnel in a safe way? And even if you could do it - Consider how huge the stations must be. They have to contain 100+ cars plus space to enter/exit them (couple seconds to come to a stop, 10s of seconds to leave the vehicle - with some people quicker than others -, 10s of seconds for other people to enter the vehicle, couple seconds to accelerate and synchronize to the flow..).
    - Robotbeat 6y ago
      Cars on freeways already regularly do sub-2 second spacing. If each vehicle had 7-16 people (as TBC plans), you’d get similar to Subway capacity. Folks who dismiss getting subway-like throughputs haven’t actually done the math.
      - welterde 6y ago
        The planned capacity is however only 4400 people per hour for the CES tunnel so about 14s spacing (some other projects even lower). One train every 90s has a capacity of more than 10000 people (and that's not even rush hour with any people standing). Sub-2 second spacing is quite unlikely to be used, since stopping distance (with 0 reaction time, which is not too unreasonable with LIDAR/RADAR) dictates around 2s spacing between vehicles (1.9s at 100km/h for teslas I believe). And while humans might be fine with ignoring safety aspects computers can't and shouldn't. Nevermind that building a subway-light vehicles (more similar to a people mover) is not really the same thing as using slightly-modified Teslas as subway replacement (which is what it seems they will be using for now)..