Musk Says Boring Company To Focus on Hyperloop to Transport Pedestrians

Elon Musk says The Boring Company is shifting its plan a bit to prioritize pedestrians and cyclists over cars.

A video the company previously published showed cars being transported on sled-like platforms. Cars would be lowered into the tunnel by street-level elevators and then transported underground at speeds up to 150 mph.

The company also teased a pod that would carry passengers, which seems to be The Boring Company’s current focus. “Will still transport cars, but only after all personalized mass transit needs are met,” Musk said in a tweet. “It’s a matter of courtesy & fairness. If someone can’t afford a car, they should go first.”

Musk said the company’s “urban loop system” would have thousands of small stations the size of a single parking space that take riders close to their destination and blend seamlessly into a city, rather than a small number of big stations like a subway. 

Musk shared a video to Twitter to offer an idea of how the concept would work.

https://twitter.com/x/status/972245615735222273

And, he accepted comparisons to a bus system.

https://twitter.com/x/status/972248154354495488

The Boring Company is currently digging a tunnel under Los Angeles, and recently received approval to dig in Washington, DC.

 

[Cloxxki]

A fast distribution system to get cars in and out of city centers will only promote bringing a car into town, or owning one when living there. Less cool to make mini-metros, but it may do the trick for some cities.

 

[gg_got_a_tesla]

Just a bit like the highways from Minority Report but, underground?!

 

[SageBrush]

I really don't think the systems are compatible. It does not look at all like the urban loop tunnels can be depressurized as pods would be entering and exiting it constantly. And the pods aren't shaped for the hyperloop type tunnels operating at a near vacuum to reduce drag. Their propulsion systems are different, too. Other than sounding like your assertions are plausible, there's so much that just doesn't fit. They are not the same systems.. one system can not just interchange with the other. The only thing they have in common is tunnels.

I suspect you are thinking too black or white.
An air density reduction to 25% of outside would let the pods travel at twice the speed for an equivalent air resistance.

In general, a drop in air pressure of to x% of normal would let the pods travel sqrt(1/x) times faster. Like so:

 

[HankLloydRight]

I suspect you are thinking too black or white.

Not really. Nothing has ever been said about urban loop transit being in partially vacuated tunnels, except in this thread.

I don't see how it would even be possible to reduce the pressure of such a system even 25% with thousands of station stops and Tram elevators constantly going into and out of the system. Not to mention the phenomenal energy needed to keep this massive multi-level system of tunnels partially vacuated, yet allow packet-switch like travel between any two points.

Vacuating the hyperloop is only possible because it's a single, sealed tube between point A and point B. No switches, no junctions, one stop on each end.

 

[HankLloydRight]

Hyperloop has been tracked, possibly roller coaster style.

Loop is showing a center something, previous video showed distinct side wheels.

First, I never said anything about Hyperloop not being tracked.

Second, it's possible to be tracked in the center for guidance, and have side wheels for propulsion.

 

[mongo]

First, I never said anything about Hyperloop not being tracked.

Second, it's possible to be tracked in the center for guidance, and have side wheels for propulsion.

And I didn't say you said Hyperloop wasn't tracked. I was clarifying that my non-track response was referring to the urban loop.

I'm not following you on the guide rail concept. If the car is resting on a center rail, that reduces friction for the drive wheels, unless it dynamically adjusts the rail force. Or are you thinking of a lateral guide like at theme park rides?

 

[HankLloydRight]

Yes, the center rail would be for guidance, not traction. There are subways that use large rubber tires on flat rails for propulsion, and a center rail for guidance and possibly power (I don't recall the European city where I saw this, perhaps Germany?). I'd still call that a tracked vehicle.

 

[RDoc]

I'd assumed the Loop rail (or slot) was the power supply and the sled drove and steered itself as an AP car does. Essentially like an electric bus, but rather than an overhead catenary, a third rail like power source. Any batteries in the sled would only be for very short distances which would keep the costs down. I think the sleds have to be cheap for this system to work.

As far as elevators for people or sleds, I vote for sleds because it eliminates the need for large underground construction. Surface boarding areas seem a lot cheaper and more flexible than underground, as well as being much more easily scalable.

 

[HankLloydRight]

, I vote for sleds because it eliminates the need for large underground construction.

Sled elevators don't need large underground construction?

I don't get why you folks can't see a simple system where people board an elevator on the surface, it goes down to a waiting pod/tram (at the proper level), both doors open, and people board directly from the elevator to the pod? No underground platforms or additional massive construction or excavation (less, actually). And one human elevator for people can handle lots of people going down for different levels of tram stops. A pod/tram elevator can only serve one route at a time. Seems phenomenally inefficient to raise and lower a pod one at a time when you could transport lots of people for different routes with just one elevator trip.

I know you fanboys are going to argue this to death. But it's just logic. As I said before, the pod elevator was necessary when you're dealing with random cars going into/out of the system. But now that it's limited to system based pods, the pod elevator just doesn't make any sense. It's expensive and inefficient for moving people around.

 

[mongo]

I'm not seeing the logic, please expound.
How is a tram sized elevator better than a tram elevator?
How do you handle an elevator with more people than will fit on the tram?
How is a tram sized elevator shaft next to the tunnel less excavation than a tram sized elevator onto the tunnel?

Regarding elevator time:
Assuming:
0.1 G acceleration limit (.15 is a standardish limit for normal elevators)
14 foot diameter tunnels.
Tunnel placed 2 diameters below surface, travel tunnel bottom at 42 ft.
Elevator transit time with half acceleration, half deceleration:
21 = 1/2*0.1*32(ft/sec)* t^2
420/32 = t^2
t^2 = 13.125
t = 3.6 seconds
Double for full travel
7.2 seconds from surface to rail.
You are not going to reliably exchange people that fast.

Other question of interest to me: Is it feasible to place the car directly on the active path? (tl;dr;sort of)

Time to clear the first 14 ft:
14 = 1/2 * 0.1 * 32 * t^2
280/32 = t^2
8.75 = t^2
t = 2.96 seconds (3)
Time to accel/decel from 120 MPH at 0.1 G
0-120 MPH @ 0.1 G
176ft/sec = 32 * 0.1 * t
t = 176/32 = 55 seconds
Total time for maneuver: 58 seconds
Total differential distance needed = (3 + 55/2) * 176 = 5,368 feet. (the half factor is due to the linear speed change)

So at 120 MPH with a 5,368 foot gap, the elevator can lift a pod off or place a pod on the active track.

If the route is 60 MPH, then only the gap needed is .
88 = 32 * 0.1 * t = 27.5 seconds to accel/decel
88 * (3+ 27.5/2) = 1,474 foot gap.

For a 30 MPH route (dense city)
12.75 accel/ decel
44 * (3 + 12.75/2) = 412.5 foot gap.

Note that this does not mean this gap is needed between each pod. Rather, the pods would create that gap by grouping so that the system can add/ remove as needed.

Note that in the 120 MPH 0.1 G case, it takes a distance of .5 * 32 * 55^2 = 48,400 ft to reach speed.
In the 60 MPH case, it's .5 * 32 * 25.7^2 = 12,100 ft.
So in the on/off ramp case, the system will either

• Need to make room for the pod
• Accelerate faster than typical subways
  
• And/ or have really long accel/ decel lanes

 

[HankLloydRight]

Yes, yawn. I could make all the same calculations with different assumptions to support my assertions. I'm not going there since I don't want to start arguing over each individual magic number assumption you made.

It's also about weight -- no matter how you cut it, a pod elevator is going to have to be built to lift the entire weight of the pod plus the max load of people. A people elevator only has to lift the elevator cab and the people... which is always going to be less than the sled+people. Less weight, less cost, faster transport.

And there is no 'active track' .. even in the video it shows the pods pulling off the active track to load/unload. How is that any different if the sled stays on the pull-out and only people are loaded/unloaded?

 

[HankLloydRight]

How is a tram sized elevator better than a tram elevator?

Because you can fit people much more densely in a human elevator for a 10 second ride than you can (or will want to) for a 5 to 10 minute transport ride to their location. It's also less weight as mentioned above. I also never said "tram sized elevator".

 

[HankLloydRight]

How is a tram sized elevator shaft next to the tunnel less excavation than a tram sized elevator onto the tunnel?

Conceptually, it's the same excavation, just that the elevator shaft is shifted to the side of the track instead of on top of it. The only marginal difference is the space of the elevator cab next to the tram/sled. Everything else is the same (or less with a human sized elevator).

 

[mongo]

Yes, yawn. I could make all the same calculations with different assumptions to support my assertions. I'm not going there since I don't want to start arguing over each individual magic number assumption you made.

It's also about weight -- no matter how you cut it, a pod elevator is going to have to be built to lift the entire weight of the pod plus the max load of people. A people elevator only has to lift the elevator cab and the people... which is always going to be less than the sled+people. Less weight, less cost, faster transport.

And there is no 'active track' .. even in the video it shows the pods pulling off the active track to load/unload. How is that any different if the sled stays on the pull-out and only people are loaded/unloaded?

The entire post was not directed to you. I had written everything regarding calculations before your post, so I just added those questions to the beginning. Sorry for the confusion. (they were not magic numbers, if you have a better source for elevator and subway accelerations, please share)

Weight only matters for elevator structure, counterweights cancel gravity, so the main effect of mass is the motor sizing, regenerative motor drive reclaims 80% of lift energy. For a properly sized motor/ counterbalanced platform, loading a tram onto the track is faster than moving an elevator and then people. Also not sure that the incremental motor and structure cost would be more than an elevator car (and cleaning/ maintenance).

Yes, the second half was my own curiosity regarding the potential removal of the side track, not related to any posted videos (other than on/off ramp length).

Because you can fit people much more densely in a human elevator for a 10 second ride than you can (or will want to) for a 5 to 10 minute transport ride to their location. It's also less weight as mentioned above. I also never said "tram sized elevator".

If the elevator and tram exchange people via two doors at the front and rear of the tram, the elevator needs to be at least as long as that distance. If it also holds the same quantity of people, it needs to be the same width as the passenger compartment.
Usability question: elevator is descending with full load of people. One person gets off a full tram, and one gets on, what happens next?

Conceptually, it's the same excavation, just that the elevator shaft is shifted to the side of the track instead of on top of it. The only marginal difference is the space of the elevator cab next to the tram/sled. Everything else is the same (or less with a human sized elevator).

So the smaller excavation comment is based on the vertical crossectional difference of the elevators multiplied by the tunnel depth being less than the vertical crossectional area of the people sized elevator times the tunnel diameter?

 

[HankLloydRight]

If the elevator and tram exchange people via two doors at the front and rear of the tram, the elevator needs to be at least as long as that distance. If it also holds the same quantity of people, it needs to be the same width as the passenger compartment.
Usability question: elevator is descending with full load of people. One person gets off a full tram, and one gets on, what happens next?

These are easy problems to solve without having a tram-lifting elevator. Two doors on the tram (enter/exit). Front door/side door on elevator (enter/exit). FILO.

So the smaller excavation comment is based on the horizontal vertical crossectional difference of the elevators multiplied by the tunnel depth being less than the horizontal vertical crossectional area of the people sized elevator times the tunnel diameter?

Fixed your post. I think you mean horizontal cross-section times depth. The shaft depth is the same for both PLUS the volume of the landing spot for the human elevator (probably smaller than the tunnel diameter). But that's not very much volume. In reality, excavating costs for the difference between a sled sized elevator and a human sized elevator is marginally small enough to assume away. My argument is why (over)engineer an entire pod lift system when human elevator technology has existed for over a century?

The other reasoning is that the original pod elevators were necessary for the "drive-on/drive-off" of any car to enter the system. The pods no longer need to drive-on/drive-off the elevators, so why lift and lower them? If we still needed to raise/lower any car, we wouldn't be having this discussion.

Also, the additional hardware/mechanics/HV connectors needed to allow each pod to connect/disconnect from the track upon every lift and lower significantly increases the cost of the sled as well as increases failure points and maintenance, compared to a pod that is on a static rail system and doesn't need to engage/disengage hundreds of times a day.

The more I think about it, the more it makes less and less sense to raise and lower the entire sled.

 

[mongo]

These are easy problems to solve without having a tram-lifting elevator. Two doors on the tram (enter/exit). Front door/side door on elevator (enter/exit). FILO.

Yah, my point was more regarding all the people that are now riding the elevator back up without having gotten on a tram.

Imagine you have to get some place a 15 minute walk away. You are going along and there is tram with space headed the way you are. You jump on. Compare that to waiting at an elevator to ride down to see if the tram has room and possibly riding back up again. Journey is now longer than just walking.

Anecdote: I've been at the wrong station for the people mover and waited 30 minutes for an empty car.

Fixed your post. I think you mean horizontal cross-section times depth. The shaft depth is the same for both PLUS the volume of the landing spot for the human elevator (probably smaller than the tunnel diameter).

Nah, I meant vertical, as in the car moves vertically or vertical axis. It is not front cross section or side cross section. I guess I could have said top cross section or foot print.

But that's not very much volume. In reality, excavating costs for the difference between a sled sized elevator and a human sized elevator is marginally small enough to assume away.

Agreed, not a big factor, and a one time (sunk?) cost.

My argument is why (over)engineer an entire pod lift system when human elevator technology has existed for over a century?

I see reasons the tramelvator works better. Known capacity, easy surveillance of people blocking the door, easier access to people in an emergency.

The other reasoning is that the original pod elevators were necessary for the "drive-on/drive-off" of any car to enter the system. The pods no longer need to drive-on/drive-off the elevators, so why lift and lower them? If we still needed to raise/lower any car, we wouldn't be having this discussion.

And what fun what that be?

Also, the additional hardware/mechanics/HV connectors needed to allow each pod to connect/disconnect from the track upon every lift and lower significantly increases the cost of the sled as well as increases failure points and maintenance, compared to a pod that is on a static rail system and doesn't need to engage/disengage hundreds of times a day.

Good point, it will need to release and reconnect. But it will already need to do that for maintenance, and the mechanism will need to handle all the on/off ramps and tunnel changes anyway. The number of on/off cycles for lifting is much less that the number of side tunnel discontinuities it passes over. If (big if) the track section is part of the lift system, and the tram has enough battery power to move on/off the lift, no disconnect is needed. What are you thinking the large cost adder is?

The more I think about it, the more it makes less and less sense to raise and lower the entire sled.

And the more I think it does. Oh boy

 

[HankLloydRight]

Imagine you have to get some place a 15 minute walk away. You are going along and there is tram with space headed the way you are. You jump on. Compare that to waiting at an elevator to ride down to see if the tram has room and possibly riding back up again. Journey is now longer than just walking.

Obviously there would be some sort of entry way/pay-gate to allow entry into the elevator only when a pod going to your location is approaching. The elevator only goes down to the tram when the tram is ready to accept passengers. In the meantime, the elevator is free to take passengers to other levels/destinations. The paygate or entry way would only allow the max number of pax on any tram. And this paygate would have to exist for both methods. This prevents the scenario you are describing. These are trivially easy problems to solve unrelated to human/pod elevator.

Nah, I meant vertical, as in the car moves vertically or vertical axis. It is not front cross section or side cross section. I guess I could have said top cross section or foot print.

A footprint would be a horizontal cross-section. The area of a horizontal cross-section, times the depth of the shaft is the total volume of the shaft. A front or side cross section is a vertical cross-section. The plane of the "section" you are talking about is horizontal.

But it will already need to do that for maintenance,

The number of times for maintenance is tiny compared how robust it would have to be to handle hundreds or thousands of times per day. It would be different technology. For maintenance, it could be a manual disconnect procedure. For pod elevators, it would have to be completely automatic and fault-free. Much much harder problem to solve.

and the mechanism will need to handle all the on/off ramps and tunnel changes anyway ...the number of on/off cycles for lifting is much less that the number of side tunnel discontinuities it passes over.

Completely different technology that a full connect/disconnect.

 

[mongo]

Obviously there would be some sort of entry way/pay-gate to allow entry into the elevator only when a pod going to your location is approaching. The elevator only goes down to the tram when the tram is ready to accept passengers. In the meantime, the elevator is free to take passengers to other levels/destinations. The paygate or entry way would only allow the max number of pax on any tram. And this paygate would have to exist for both methods. This prevents the scenario you are describing. These are trivially easy problems to solve unrelated to human/pod elevator.

In the tramelvator scenario, people can easily see capacity, and it would have signage for route or pure dynamic function based on your app profile. App could also be the way to charge travel fees. If it requires queues and turnstiles at the street level, that is much more area used plus slows things down.
App use/ request also allow for the hailing of the pod as you walk toward a tram station. If that is not done till the turnstile, then there is less time for the system to get a pod in place.

The system does lend itself to free for all usage.

The number of times for maintenance is tiny compared how robust it would have to be to handle hundreds or thousands of times per day. It would be different technology. For maintenance, it could be a manual disconnect procedure. For pod elevators, it would have to be completely automatic and fault-free. Much much harder problem to solve.

Existing subways and trolleys with catenary wires do this (slip connections) currently. Is it a hard engineering problem?

Completely different technology that a full connect/disconnect.

Right, it would eliminate the need for full disconnection, thus avoiding that difficultly,

 

[HankLloydRight]

In the tramelvator scenario, people can easily see capacity, and it would have signage for route or pure dynamic function based on your app profile.

Would be no different for the human elevator. You would be told when/where to take an elevator. It's not a problem that needs solving.

Well, since neither of these things are ever going to happen, I just don't have the time or energy to keep beating this to death.