Elon Musk tweets a date for the opening of his first Los Angeles tunnel

People will be able to take a 155mph ride under the streets of Hawthorne.

Read the whole story

 

[gypsumfantastic]

Remember: All Elon Musk tweets are believed to be accurate at the time of writing by Elon Musk.

 

[maehara]

The CEO added that there will be an opening event on the evening of December 10

Can't help but note that no year was included there. Bearing in mind the Elon Time phenomenon, 2018 not guaranteed....

 

[iPirateEverything]

Looking forward to seeing it!

 

[cjbrigol]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

That's insane haha

 

[Don Reba]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

That's insane haha

Kind of like discarding rockets after a single use.

 

[Peevester]

If you're reaching 155mph in a two mile tunnel, you're accellerating or decellerating at about a gee for the entire time, and it's over in half a minute. Whee!

Edit: Well that calculation sucked - I somehow shortened the tunnel by a LOT (to about a half mile). Here's a possibly more accurate ride profile:

At one gee, you get to 155mph in about 800 feet (and 7 seconds). So, you spend 14 seconds accellerating and decelerating, and 39 seconds at cruising speed. I'm still going whee!

 

[coconutboy]

Musk tweeted last night that pods in the tunnel will achieve a top speed of 155 mph (250 km/h). The CEO added that there will be an opening event on the evening of December 10, and free rides for the public on the following day.

If this actually happens, the line of people wanting a ride will be like going to Disneyland in the summer. Even if the pods only hit 60mph there will still be throngs for blocks. Most of us Americans never experience the awesome fun of doing ~130+ mph unless it’s in a plane. Triple digit Fast and Furious in a tunnel bubble? Might as well be offering free ice cream BBQ and beer; EVERYBODY is coming to that party!

 

[cate]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

 

[John Cale]

I would love to see the waiver for that free ride...

 

[Peevester]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

It's totally true. Traditional boring machines are not reused. They dig them into a side tunnel and leave them there, or even bury them, because they are too difficult to disassemble again onsite, and generally they use a machine from both ends (not one bore through the whole thing), so it's not like the machine can just drive through the exit.

This kind of crazy is one of the major planned advantages of Boring.

 

[rosen380]

Musk tweeted last night that pods in the tunnel will achieve a top speed of 155 mph (250 km/h). The CEO added that there will be an opening event on the evening of December 10, and free rides for the public on the following day.

If this actually happens, the line of people wanting a ride will be like going to Disneyland in the summer. Even if the pods only hit 60mph there will still be throngs for blocks. Most of us Americans never experience the awesome fun of doing ~130+ mph unless it’s in a plane. Triple digit Fast and Furious in a tunnel bubble? Might as well be offering free ice cream BBQ and beer; EVERYBODY is coming to that party!

Not quite 130 MPH--- but if you are near Six Flags Great Adventure [NJ] or Cedar Point [OH], they have coasters that hit 120+ MPH -- and you could argue that 120+ in an open-air coaster probably feels faster than 130 in an enclosed pod...

 

[Bloater51]

Tunnelling machines vary a great deal in size and in the conditions in which they are required to work. There may be several of them on a project and they cannot simply reverse out (the tunnel is build behind as they dig). But if anyone is interested in what is involved in moving a large one intact, this paper explains the problems.

Musk's tunnel is small bore, of course, and probably nothing like the monsters normally used for urban mass transport projects.

 

[dragonzord]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

It's totally true. Traditional boring machines are not reused. They dig them into a side tunnel and leave them there, or even bury them, because they are too difficult to disassemble again onsite, and generally they use a machine from both ends (not one bore through the whole thing), so it's not like the machine can just drive through the exit.

This kind of crazy is one of the major planned advantages of Boring.

If only Musk had some experience in making reusable machinery

 

[Deleted member 543677]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

Exhibit A : Where are the boring machines for the English Channel Tunnel ? (Hint there were boring machines starting from each end of the central tunnel meeting in the middle)

 

[rosen380]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

Exhibit A : Where are the boring machines for the English Channel Tunnel ? (Hint there were boring machines starting from each end of the central tunnel meeting in the middle)

One example doesn't make it "the case" or even typical. You need data for your assertion not anecdotes.

[edit] And if you only have one example, how about one that is fully true?

https://en.wikipedia.org/wiki/Channel_Tunnel#Completion

"the UK TBMs were driven steeply downwards and buried clear of the tunnel. These buried TBMs were then used to provide an electrical earth. The French TBMs then completed the tunnel and were dismantled."

So, none of the five from the French side were buried and the ones from the English side ultimately served a purpose.

 

[Cloudgazer]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

Exhibit A : Where are the boring machines for the English Channel Tunnel ? (Hint there were boring machines starting from each end of the central tunnel meeting in the middle)

Well amusingly enough one ended up on ebay

http://news.bbc.co.uk/1/hi/business/3620673.stm

But several were indeed buried.

 

[MobiusPizza]

So, they're building subways now? Why is this news?

Because this is boring news.

 

[mmiller7]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

That's insane haha

Kind of like discarding rockets after a single use.

Except at least rockets there's (in my mind) the complex issue of recovering something needs to be minimal weight and also has been subject to high G-forces and fire.

I'd have assumed a tunnel boring machine they would just tow it out the same way it went in?

 

[MrWalrus]

So, they're building subways now? Why is this news?

If the subway reached 155mph, that'd be news.

 

[ivan256]

How is it possible that the date for this wasn't April 20th?

 

[NinjaNerd56]

Paging Irwin Allen...Irwin Allen; your disaster movie about a runaway hyperloop capsule is calling.

 

[VVrath]

If you're reaching 155mph in a two mile tunnel, you're accellerating or decellerating at about a gee for the entire time, and it's over in half a minute. Whee!

Not even close. Assuming constant acceleration to the midpoint followed by constant deceleration to the end:

155mph = ~ 70 m/s, s = 1 mile = 1609m
Substituting into V^2 = U^2 + 2as:
70^2 = 0 + (2 * a * 1609)
a = 4900 / 3218
a = ~1.522 m/s/s, or roughly one-seventh-of-a-gee

 

[Skyfire77]

Top secret video of one of the test runs!

Spoiler

 

[Pusher of Buttons]

I never know anymore with Musk tweets if we're on the verge of a amazing scientific or social revolution or the victim of a Absinthe binge fueled vision

 

[raxx7]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

Are you sure? Often there is an exit point of tunnels, so boring machines are often extracted and used again.

As far I know, the boring machines are keep in they graveyard when there are some kind of collapse (not so seldom). In such cases, it is often better to stabilize soil, and thus burying the machine (and adding concrete) than extract it. But this is just because collateral damages in cities costs much more than a boring machine.

Exhibit A : Where are the boring machines for the English Channel Tunnel ? (Hint there were boring machines starting from each end of the central tunnel meeting in the middle)

One example doesn't make it "the case" or even typical. You need data for your assertion not anecdotes.

Actually, his example is half wrong, half correct.
The TBM's which dug the channel tunnel from the French side were disassembled and removed while the ones which dug from the UK side were buried.

It's also important to note that when one says that a TBM is buried, one is referring mainly to the front section which does the actual boring, installs ring segments, etc.
And even that section may be gutted before burial.

That said, speaking of lack of evidence, I don't see any evidence that tunnel construction costs are being significantly increased by lack of TBM re-use.
Eg, in New York, the TBM which dug the East Side Access tunnels was buried.

It was estimated that a new TBM would cost about 6-8E6 USD and that extracting it would have cost 9E6 USD.
https://untappedcities.com/2017/02/09/t ... de-access/

Overall, the project cost 4.3E9 USD. The TBM's costs are drop in the bucket.

 

[Mongo McMongo]

" Traditional boring operations have been known to just bury their machines in the ground once a tunnel is done because it's more expensive to find a way to get the massive piece of equipment out."

That's insane haha

Kind of like discarding rockets after a single use.

Except at least rockets there's (in my mind) the complex issue of recovering something needs to be minimal weight and also has been subject to high G-forces and fire.

I'd have assumed a tunnel boring machine they would just tow it out the same way it went in?

Most tunnels need lining, which reduces the diameter. So at least the front "shield" with the boring rotors would need to be dismantled before reversing. And beyond lining a transport tunnel then gets rails or a roadway, maybe lights, control/signalling gear, etc - it would add a lot of latency if you have to wait until the boring machine is extracted before even starting on this work.

 

[raxx7]

And beyond lining a transport tunnel then gets rails or a roadway, maybe lights, control/signalling gear, etc - it would add a lot of latency if you have to wait until the boring machine is extracted before even starting on this work.

Behind the TBM there's usually lot of auxiliaries filling the tunnel: conveyour belt for earth removal, something to take new ring segments, etc.
So first the tunnel is dug, then the auxiliaries are removed and only then you start to finalize the tunnel.

 

[Peevester]

If you're reaching 155mph in a two mile tunnel, you're accellerating or decellerating at about a gee for the entire time, and it's over in half a minute. Whee!

Not even close. Assuming constant acceleration to the midpoint followed by constant deceleration to the end:

155mph = ~ 70 m/s, s = 1 mile = 1609m
Substituting into V^2 = U^2 + 2as:
70^2 = 0 + (2 * a * 1609)
a = 4900 / 3218
a = ~1.522 m/s/s, or roughly one-seventh-of-a-gee

Yeah, I think I halved the distance to do a straight calculation of acceleration, and then somehow halved it again, so blargh, that was totally wrong.

Let's try it again: At one gee, you get to 155mph in about 800 feet (and 7 seconds). So, you spend 14 seconds accellerating and decelerating, and 39 seconds at cruising speed. I'm still going whee!

 

[Luv2Calculate]

Wow. I know how strong the air blast can be that is pushed out in front of a regular subway going at only 70 kph or so. I've seen many an umbrella fly just before the metro arrives at the station. And that was in the middle of a line, where the air gets pushed onward into the rest of the tunnel. Not at a dead end like this 2-mile underground drag strip will be.

I assume they'll make some big air vents somewhere. I wouldn't want to stand near one though.


On that topic: https://www.youtube.com/watch?v=7LzMX-z8W50

 

[eltari]

If you're reaching 155mph in a two mile tunnel, you're accellerating or decellerating at about a gee for the entire time, and it's over in half a minute. Whee!

Not even close. Assuming constant acceleration to the midpoint followed by constant deceleration to the end:

155mph = ~ 70 m/s, s = 1 mile = 1609m
Substituting into V^2 = U^2 + 2as:
70^2 = 0 + (2 * a * 1609)
a = 4900 / 3218
a = ~1.522 m/s/s, or roughly one-seventh-of-a-gee

Yeah, I think I halved the distance to do a straight calculation of acceleration, and then somehow halved it again, so blargh, that was totally wrong.

Let's try it again: At one gee, you get to 155mph in about 800 feet (and 7 seconds). So, you spend 14 seconds accellerating and decelerating, and 39 seconds at cruising speed. I'm still going whee!

Who the hell wants to accelerate at a g as anything more than an amusement ride?

 

[Peevester]

If you're reaching 155mph in a two mile tunnel, you're accellerating or decellerating at about a gee for the entire time, and it's over in half a minute. Whee!

Not even close. Assuming constant acceleration to the midpoint followed by constant deceleration to the end:

155mph = ~ 70 m/s, s = 1 mile = 1609m
Substituting into V^2 = U^2 + 2as:
70^2 = 0 + (2 * a * 1609)
a = 4900 / 3218
a = ~1.522 m/s/s, or roughly one-seventh-of-a-gee

Yeah, I think I halved the distance to do a straight calculation of acceleration, and then somehow halved it again, so blargh, that was totally wrong.

Let's try it again: At one gee, you get to 155mph in about 800 feet (and 7 seconds). So, you spend 14 seconds accellerating and decelerating, and 39 seconds at cruising speed. I'm still going whee!

Who the hell wants to accelerate at a g as anything more than an amusement ride?

And you think he's not going to run it like an amusement ride? COME ON, this is Elon Musk.

Hell, he may accellerate faster than that, though I doubt he'd decelerate at more than a gee for comfort's sake, since having your circulation cut off by a harness is no fun.

 

[deviltry]

Everyone who will not use this tunnel is a pedo.

 

[halse]

the two big advantages of this approach relative to a subway line are:
1. the tunnels are about the diameter of a main sewer line-- this is a lot easier to excavate and support than a subway line size tunnel and the tunnel does not have to be very deep
2. the boring machines can be much smaller and much faster than those used for a subway line, reusing the machines is a bonus

 

[Peevester]

Wow. I know how strong the air blast can be that is pushed out in front of a regular subway going at only 70 kph or so. I've seen many an umbrella fly just before the metro arrives at the station. And that was in the middle of a line, where the air gets pushed onward into the rest of the tunnel. Not at a dead end like this 2-mile underground drag strip will be.

I assume they'll make some big air vents somewhere. I wouldn't want to stand near one though.

On that topic: https://www.youtube.com/watch?v=7LzMX-z8W50

This is an interesting question. I assume there are big air vents at each end? Or maybe the "pods" don't block as much of the tunnel as a subway car does, so it's not as much of an issue.