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-   -   CHICAGO: Transit Developments (https://skyscraperpage.com/forum/showthread.php?t=101657)

bnk Jun 14, 2018 10:46 PM

Quote:

Originally Posted by PKDickman (Post 8221498)
I also imagine that the the difficulty in extracting the spoils from a 7-15 mile long tunnel gets a lot higher as the tunnel diameter gets smaller.

I wonder if Musk and the Boring co have ever tested out Chicago's blue clay.

That is not like a crumbled rock that can be just put on a convertor.

It used to be hand cut with large sword like curved knives back the 00 Aughts, 1910-39's. And carried away by a simple coal mine type of narrow track railway.

https://upload.wikimedia.org/wikiped...nstruction.jpg
Tunnel under construction in 1902. The freshly cut clay ahead of the concrete work shows clear knife marks.



My grandfather did this 6 days a week, almost cost him his life. So my question is is can the Boring co MacInnes cut right through dense wet grey clay the seems to be in a abundance?


Perhaps Glowrock has some incite? The Boring co is similar to other large bore drilling rigs but the clam they can do it at 1/5 the cost while removing only a 1/4 amount of earth to be removed and used elsewhere like fill and what not.


Also what can Glowrock tell or educate us on this blue clay we have underneath us?

ardecila Jun 14, 2018 11:41 PM

Quote:

Originally Posted by jmecklenborg (Post 8221478)
The Boring Company has yet to build a boring machine. The test tunnel in Hawthorne is merely an old Metrorail tunnel that dug gold line light rail tunnels. Boring machines take a long time to design and manufacture, so Mr. Musk won't be digging jack squat for at least a year and more like two. As usual, he made the Trump-like outrageous claim that he'll be digging in 3 months.

I don't think he ever claimed he would build his own TBMs, merely that he would use small-diameter ones, normally used for sewer and utility construction, for a transportation use instead, and B) that he would automate them to the greatest extent possible. The debacle around East Side Access in NY has certainly shown that tunnel construction in America is often over-staffed with highly-paid workers. A public project using taxpayer dollars will find it hard to avoid capture by union politics, but an all-private project has far greater leverage even if it does employ unionized workers.

Quote:

There are serious problems with this proposal both as an economically viable project and as a model for anything else. It's main cost-saving plan is to build a very small-diameter tunnel, only 14 feet instead of the industry standard 19-21-foot for light rail and subway tunnels. This promises to save a huge amount of money but there are many reasons why this hasn't been done in the past, or at least since the Glasgow subway and first London tube lines were built.
I mean, the reason is capacity. If you're trying to move the masses, it's difficult to do so in a narrow tunnel. Frequent station stops and the need for safe braking distance limit just how often you can safely run trains in a tunnel... if you can only run a train every 2 minutes, you'd better make sure that train is big enough to handle the crowds that arrive at peak. That in turn demands long vehicles with at least enough room for two rows of seats and an aisle that is conducive to wheelchairs.

But again, airport travelers are a niche market that is a tiny, tiny fraction of the passenger demands that normal subway/metro systems are expected to handle. This is a premium service with a limited capacity, and if it draws large crowds than Musk will increase the ticket price until capacity equals supply. He's free from the usual politics around transit fares, because the voting public will see the riders of this system as wealthy out-of-towners.

Quote:

The first big reason is capacity -- it only costs incrementally more to build a system that can carry 10x as many passengers. The second is that the only way to make an emergency exit from those old subway lines is to walk out either end of the train and then between the tracks. This Chicago proposal has the same problem and it's unlikely that the narrow tunnel will be approved for that reason. To get to an emergency exit, escaping passengers would have to walk out the front or back of their "skate" and then through other stopped "skates" in order to reach an exit.
I too am interested in the emergency plan. Since the cars are self-propelled, they don't rely on any outside power source or signal system. Walking down the tracks isn't dangerous if there's no third rail and all vehicles are stopped. It's possible Musk could build self-closing bulkhead doors at various points to isolate the tunnel into segments and prevent smoke from spreading, and then program any (functioning, occupied) cars to move (forward or backward) to the nearest egress point.

Quote:

Also, do Musk's terrible ridership/revenue projection. 5,000 passengers per day paying $25 each is only $125k a day in gross revenue to pay off $1 billion+ in debt. This is an absolutely terrible business proposition. Who is going to invest in this other than Musk throwing down his own money as a hobby?
Musk is probably assuming the fares will increase over time while the principal and interest on construction will remain fixed. Remember, he's offering a product that is superior to every transportation option that exists right now, including a taxi ride on an free-flowing Kennedy.

jmecklenborg Jun 14, 2018 11:45 PM

Quote:

Originally Posted by PKDickman (Post 8221498)
I also imagine that the the difficulty in extracting the spoils from a 7-15 mile long tunnel gets a lot higher as the tunnel diameter gets smaller.

Yeah, a normal industry consultant could answer this for us. But Musk will always distort and make everything look way easier and cheaper than it is.

If the circular tunnel is only 14 feet wide that means the "roadway" is only 6-8 feet wide which means to standard pieces of machinery can't pass each other inside the tunnel. If they're lucky, two bobcats or fork lifts could pass each other, but not anything much bigger. That means something big that needs to go into the tunnel needs to clear absolutely everything out of the way.

Is the FTA going to require emergency exits and regularly spaced connections between the parallel tunnels? Of course. These are huge expenses. I fear that the "regulations" Musk fears are the safety requirements that contribute to tunneling projects being very expensive. Not sure how he skirts federal law.

What advantage do Musk's "skates" have over running Vancouver sky train-type automatic trains? None other than the promise of saving some money outfitting the tunnels but running battery-powered trains. But it's unlikely that that is going to save much money long-term.

PKDickman Jun 14, 2018 11:56 PM

Quote:

Originally Posted by jmecklenborg (Post 8221580)
Yeah, a normal industry consultant could answer this for us. But Musk will always distort and make everything look way easier and cheaper than it is.

If the circular tunnel is only 14 feet wide that means the "roadway" is only 6-8 feet wide which means to standard pieces of machinery can't pass each other inside the tunnel. If they're lucky, two bobcats or fork lifts could pass each other, but not anything much bigger. That means something big that needs to go into the tunnel needs to clear absolutely everything out of the way.

You also need to get lining materials in while your hauling the muck out.
Musk's talked of using the spoils as part of the lining but he's not to specific about how one would do that.
In any event, I think it highly unlikely that he'll find himself burrowing through a vein of portland cement.

jmecklenborg Jun 15, 2018 3:12 AM

Here is a photo of the Chunnel under construction back in 1990~:

http://i81.photobucket.com/albums/j2...pshmc1ucjw.jpg

As you can see there was enough space in each main tube for a narrow gauge work train to operate in each direction. Plus, they had the center service tube as well.

We're talking about a 16-mile tunnel here...not 2 or 3 miles. Plus, the downtown terminus is in the center of Dowtown Chicago, so they're probably only going to need a center launch pit where they send a pair of TBM's toward Downtown Chicago and another pair toward O'Hare.

The more-or less exact halfway point is this city park:
https://www.google.com/maps/place/Ch...!4d-87.6297982

So Musk is going to show up in three months, tear this park up to build a launch pit, and then we'll have a parade of dump trucks hauling spoil out for the next 3 years.

Musk also provided zero details on the O'Hare station. It will have to be basically right next to the existing underground blue line station in order to be competitive with the existing blue line local service. Otherwise, if the Muskrail station is out in long-term parking, people are going to have to transfer to a shuttle bus or the tram and their total time to the airport gates is going to be the exact same that it is now.

ardecila Jun 15, 2018 3:43 AM

Not sure why you picked Portage Park. It won't be a straight shot that totally ignores the street grid. Boring Co will try to avoid dealing with private property owners or purchasing easements, so the route will follow city streets, railroads and expressways to the greatest extent possible. I assume they will seek out small industrial properties for ventilation and launch box.

I kinda figured the O'Hare terminus would just be a deep basement below T2. Since the Boring Co alignment is totally underground, it doesn't have to follow I-190, the tunnel might some in from the south or directly from the east.

jpIllInoIs Jun 15, 2018 1:30 PM

Quote:

Originally Posted by jmecklenborg (Post 8221775)
We're talking about a 16-mile tunnel here...not 2 or 3 miles. Plus, the downtown terminus is in the center of Dowtown Chicago, so they're probably only going to need a center launch pit where they send a pair of TBM's toward Downtown Chicago and another pair toward O'Hare.

The more-or less exact halfway point is this city park:
https://www.google.com/maps/place/Ch...!4d-87.6297982

So Musk is going to show up in three months, tear this park up to build a launch pit, and then we'll have a parade of dump trucks hauling spoil out for the next 3 years.

It already been announced that it will follow the street grid under Elston Ave in this area. This is a completely usable and empty lot at Elston and Foster at a similar halfway point.. The arial view show an old factory, but the Streetview reveals it has been razed and is awaiting development.

rlw777 Jun 15, 2018 1:47 PM

Quote:

Originally Posted by jmecklenborg (Post 8221478)

Also, do Musk's terrible ridership/revenue projection. 5,000 passengers per day paying $25 each is only $125k a day in gross revenue to pay off $1 billion+ in debt. This is an absolutely terrible business proposition. Who is going to invest in this other than Musk throwing down his own money as a hobby?

The projected cost is between $500 million and $1 billion actually and you're not taking into account advertising revenue. But also Musk seems more interested in proving the tech and selling to other cities than making bank on this one. He said it himself "it might not make much money, but it would show others the technology works and can be useful."

rlw777 Jun 15, 2018 1:50 PM

Here's the proposed route of the tunnel/s from ChiTrib

http://www.trbimg.com/img-5b22cf25/t.../1200/1200x675

ardecila Jun 15, 2018 2:23 PM

I'm not sure that's confirmed, Steve Rivkin indicated the route was still tentative. I doubt it makes sense to follow I-190's zig-zag route into the airport, for example, the curves would impose a speed restriction. As for the urban portion - if the tunnel is shallow in the clay stratum, it makes sense to follow city streets instead of the expressway corridor, that way the TBM isn't dodging around the caissons for expressway overpasses and such.

On the other hand, it may be easier for the TBM to go deep into the limestone bedrock (>100 feet down, roughly). Then there is far less concern of building settlement, and the rock is soft enough that it can be bored fairly easily.

LouisVanDerWright Jun 15, 2018 2:29 PM

Quote:

Originally Posted by ardecila (Post 8222087)
I'm not sure that's confirmed, Steve Rivkin indicated the route was still tentative. I doubt it makes sense to follow I-190's zig-zag route into the airport, for example, the curves would impose a speed restriction. As for the urban portion - if the tunnel is shallow in the clay stratum, it makes sense to follow city streets instead of the expressway corridor, that way the TBM isn't dodging around the caissons for expressway overpasses and such.

On the other hand, it may be easier for the TBM to go deep into the limestone bedrock (>100 feet down, roughly). Then there is far less concern of building settlement, and the rock is soft enough that it can be bored fairly easily.

Lol, not going to happen, rock tunnel for this? No way. As I mentioned earlier, Chicago's soft clay is actually perfect for tunneling, its just keeping it dry and safe that's expensive. A TBM in our soil is likely mostly limited by how quickly they can remove the tailings behind it. If you think about it there is no reason why a machine with rotating cutting bits like that couldn't chew through a thousand feet of clay a day if the tunnel lining and tailing removal can keep up.

jmecklenborg Jun 15, 2018 2:51 PM

The whole point of a bored urban tunnel is that it doesn't have to follow the street grid. This thing isn't going to have intermediate stations that need to be at major intersections.

So it looks like Musk is going to try to sneakily saddle the city/waterworks/sewer district with many expenses. This is what snakes do, and Musk is a snake. There is going to be plenty of Hollywood accounting. Musk will never reveal the true cost of this project to his company, and then he'll dismiss the costs he'll push on the public.

A straight tunnel would permit higher speed. For this thing to travel at 125mph the turning radius will need to be fairly high. Something is really fishy with this plan.


Quote:

The projected cost is between $500 million and $1 billion actually and you're not taking into account advertising revenue. But also Musk seems more interested in proving the tech and selling to other cities than making bank on this one. He said it himself "it might not make much money, but it would show others the technology works and can be useful."
The actual cost will be way over $1 billion. The Boring Company has no new technology. They're just going to spec out a typical TBM and some other company will build it and they'll stamp their logo on it and it'll be all over Twitter and everyone will think that Musk invented the TBM.

This is not the "hyperloop". There is no vacuum tube. It's just going to be single-car light rail vehicles, possibly on narrow gauge track, running on batteries instead of third rail or overhead wire. Or maybe they'll totally change their minds. Or maybe they'll abandon the project when they realize it's going to cost billions and only bring in $100k per day in gross revenues.

Busy Bee Jun 15, 2018 3:10 PM

I believe our forefathers used the term "folly" .

ardecila Jun 15, 2018 3:13 PM

The last thing you'd want on a penny-pinching private tunnel project is million-dollar lawsuits with building owners along the route after their buildings start settling.

But it does seem like new EPB tunnel machines have largely solved the settlement problem by pumping foam into the clay ahead of the cutter, and then keeping the resulting slurry in a pressurized chamber behind the cutter.

Video Link

Dblcut3 Jun 15, 2018 4:20 PM

Musk's whole Boring Company and Hyperloop raises red flags to me. He seems to know nothing about transit, yet he has all these plans nationwide. And for example, why is he wanting to invest in a tunnel from Baltimore to DC but also want to invest in Hyperloops that could do basically the same thing? I just don't understand any of Musk's transit ambitions personally - they always seem super rushed and ignore critical details/issues that would need addressed.

Flancrest Jun 15, 2018 5:26 PM

Quote:

Originally Posted by jmecklenborg (Post 8221775)
Here is a photo of the Chunnel under construction back in 1990~:

http://i81.photobucket.com/albums/j2...pshmc1ucjw.jpg

As you can see there was enough space in each main tube for a narrow gauge work train to operate in each direction. Plus, they had the center service tube as well.

We're talking about a 16-mile tunnel here...not 2 or 3 miles. Plus, the downtown terminus is in the center of Dowtown Chicago, so they're probably only going to need a center launch pit where they send a pair of TBM's toward Downtown Chicago and another pair toward O'Hare.

The more-or less exact halfway point is this city park:
https://www.google.com/maps/place/Ch...!4d-87.6297982

So Musk is going to show up in three months, tear this park up to build a launch pit, and then we'll have a parade of dump trucks hauling spoil out for the next 3 years.

Musk also provided zero details on the O'Hare station. It will have to be basically right next to the existing underground blue line station in order to be competitive with the existing blue line local service. Otherwise, if the Muskrail station is out in long-term parking, people are going to have to transfer to a shuttle bus or the tram and their total time to the airport gates is going to be the exact same that it is now.

Hmm agenda much?

F1 Tommy Jun 15, 2018 6:00 PM

This is perfect project for Musk. We deep down know this hasn't a hope in hell of being completed properly ever by him without a government bailout plan.
By the planned finish date of this project Tesla should already be in liquidation!!!

Flancrest Jun 15, 2018 6:49 PM

Is musk hate the new altright thing? I mean yeah spacex is shitting all over the fat pork red states that build space tech. Not to mention the hit russia is taking. And Tesla is making oil companies piss themselves.


Idk. Makes me go hmmm.

F1 Tommy Jun 15, 2018 6:59 PM

Quote:

Originally Posted by Flancrest (Post 8222387)
Is musk hate the new altright thing? I mean yeah spacex is shitting all over the fat pork red states that build space tech. Not to mention the hit russia is taking. And Tesla is making oil companies piss themselves.


Idk. Makes me go hmmm.

No, his ideas are sometimes great. His business plans on the other hand leave a lot to be desired. Tesla will be gone before the "oil companies" have anything to worry about.

left of center Jun 15, 2018 7:07 PM

Two of Musk's big risky endeavors were Tesla and SpaceX, and people in the media crapped all over him and his supposed attempts to reshape from scratch the automotive and space launch industries. Now, every single legacy auto manufacturer cant make or plan electric vehicles fast enough, and SpaceX is literally NASA's go to for getting payloads into space. While Musk may not know all of the exact specifics of transportation now, I think he has proven himself an adept learner and one that quickly becomes proficient in the industry he is looking to turn upside down.

TL;DR: This isn't his first rodeo, and his naysayers typically end up eating their own shoe in the end.


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