Hyperloop: Pipes of Fancy

Post by Robotbeat » Thu, Aug 20, 2020, 4:56 PM UTC

welterde wrote: post #320

Robotbeat wrote: post #318

Earlier quoted context omitted.

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.

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…

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.

Post by welterde » Fri, Aug 21, 2020, 12:50 PM UTC

Robotbeat wrote: post #321

welterde wrote: post #320

Earlier quoted context omitted.

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…

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.

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)..

Re: Hyperloop: Pipes of Fancy

Re: Hyperloop: Pipes of Fancy