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How is it that the logic is flawed? There are real-world examples of undersized tunnels limited the growth of a subway network. London was specifically called o

How is it that the logic is flawed? There are real-world examples of undersized tunnels limited the growth of a subway network. London was specifically called out in the article.

stcredzero 8y ago
How is it that the logic is flawed? It's the exact opposite of YAGNI. It's attempting to build the ultimate end-all be-all up front. No wonder tunnel building is expensive, and all the projects wind up huge and bloated. There are real-world examples of undersized tunnels limited the growth of a subway network. London was specifically called out in the article. If a larger tunnel to Dodger stadium is needed, why couldn't it be dug below, with the old tunnel used to carry infrastructure for the new tunnel? That seems a solvable technical feat.
- discodave 8y ago
  It sounds like you're trying to bring a software mindset to an infrastructure problem, which is somewhat laudable, but ultimately misguided in this instance. In this instance, as others have pointed out, it's already clear that the Tunnel Elon is proposing doesn't carry enough passengers to make a dent in the transportation load for the stadium.
  - stcredzero 8y ago
    It sounds like you're trying to bring a software mindset to an infrastructure problem It's more that I'm pointing out that the tunneling industry is stuck in a "tunnels are big, expensive, end-all be-all projects" which creates a self-fulfilling prophecy, precluding the development of radically cheaper tunneling technologies.
- takk309 8y ago
  I am not familiar with the soil under LA but in many cases it gets much more expensive to "stack" tunnels. The construction of the upper tunnel relies on the stability of the soils underneath for support. Constructing a tunnel underneath may require the lower tunnel to be much stronger to support the loads. Why not just build the tunnel larger in the first place? If Musk wants to construct these tunnels, that if fine but I feel that the City of LA would be foolish to allow him to do it without ensure that the tunnels can be used for larger vehicles if the "skate" concept proves to be inadequate. This would come at little extra expense and would still allow Musk to test his concept but have a contingency plan if it does not work.
- jcranmer 8y ago
  > It's the exact opposite of YAGNI. It's attempting to build the ultimate end-all be-all up front. No wonder tunnel building is expensive, and all the projects wind up huge and bloated. The cost of making an incremental change to software is not appreciably different from incorporating the change in the first place. The same does not hold true for infrastructure; even a minor retrofit can end up being very expensive, especially if there was no provisioning for it. Look at the impact of the Rosslyn station on the DC Metro: the only practical solution to the capacity issue is to bore new Blue Line tunnels and a new underground station, which can't be had for less than ~$1 billion. Provisioning to solve this at the original system construction would have cost somewhere in the region of $300 million or so (there are other, much cheaper alternatives that can't be built with the current track geometry). By saving $300 million, you're ultimately setting yourself to spend 3 times that much in the future. > If a larger tunnel to Dodger stadium is needed, why couldn't it be dug below, with the old tunnel used to carry infrastructure for the new tunnel? That seems a solvable technical feat. Undermining a tunnel is the easiest way to do this, but it requires closing the old tunnel to do. Digging a new tunnel immediately underneath an old tunnel is going to introduce different stresses on the old tunnel, which is going to be more of an issue if you're boring a parallel tunnel rather than a cross tunnel. Furthermore, all of the access points now have to go deeper to reach the new tunnel, which could introduce passenger circulation issues. It will also have passenger circulation issues during construction. Maintaining access to existing infrastructure during construction is complex after all.
  - stcredzero 8y ago
    Digging a new tunnel immediately underneath an old tunnel is going to introduce different stresses on the old tunnel So then dig the new tunnel beside it. Maintaining access to existing infrastructure during construction is complex after all. For many complex industries, there is innovation and cost reduction. Digging larger parallel tunnels is something that the industry should be making easier and cheaper, leveraging the existing infrastructure. The mindset that "tunneling is expensive" is exactly the kind of self-fulfilling prophecy which prevents such progress.
    - jcranmer 8y ago

How is it that the logic is flawed? There are real-world examples of undersized tunnels limited the growth of a subway network. London was specifically called out in the article.

stcredzero 8y ago

How is it that the logic is flawed? It's the exact opposite of YAGNI. It's attempting to build the ultimate end-all be-all up front. No wonder tunnel building is expensive, and all the projects wind up huge and bloated. There are real-world examples of undersized tunnels limited the growth of a subway network. London was specifically called out in the article. If a larger tunnel to Dodger stadium is needed, why couldn't it be dug below, with the old tunnel used to carry infrastructure for the new tunnel? That seems a solvable technical feat.

discodave 8y ago
It sounds like you're trying to bring a software mindset to an infrastructure problem, which is somewhat laudable, but ultimately misguided in this instance. In this instance, as others have pointed out, it's already clear that the Tunnel Elon is proposing doesn't carry enough passengers to make a dent in the transportation load for the stadium.
- stcredzero 8y ago
  It sounds like you're trying to bring a software mindset to an infrastructure problem It's more that I'm pointing out that the tunneling industry is stuck in a "tunnels are big, expensive, end-all be-all projects" which creates a self-fulfilling prophecy, precluding the development of radically cheaper tunneling technologies.
takk309 8y ago
I am not familiar with the soil under LA but in many cases it gets much more expensive to "stack" tunnels. The construction of the upper tunnel relies on the stability of the soils underneath for support. Constructing a tunnel underneath may require the lower tunnel to be much stronger to support the loads. Why not just build the tunnel larger in the first place? If Musk wants to construct these tunnels, that if fine but I feel that the City of LA would be foolish to allow him to do it without ensure that the tunnels can be used for larger vehicles if the "skate" concept proves to be inadequate. This would come at little extra expense and would still allow Musk to test his concept but have a contingency plan if it does not work.
jcranmer 8y ago
> It's the exact opposite of YAGNI. It's attempting to build the ultimate end-all be-all up front. No wonder tunnel building is expensive, and all the projects wind up huge and bloated. The cost of making an incremental change to software is not appreciably different from incorporating the change in the first place. The same does not hold true for infrastructure; even a minor retrofit can end up being very expensive, especially if there was no provisioning for it. Look at the impact of the Rosslyn station on the DC Metro: the only practical solution to the capacity issue is to bore new Blue Line tunnels and a new underground station, which can't be had for less than ~$1 billion. Provisioning to solve this at the original system construction would have cost somewhere in the region of $300 million or so (there are other, much cheaper alternatives that can't be built with the current track geometry). By saving $300 million, you're ultimately setting yourself to spend 3 times that much in the future. > If a larger tunnel to Dodger stadium is needed, why couldn't it be dug below, with the old tunnel used to carry infrastructure for the new tunnel? That seems a solvable technical feat. Undermining a tunnel is the easiest way to do this, but it requires closing the old tunnel to do. Digging a new tunnel immediately underneath an old tunnel is going to introduce different stresses on the old tunnel, which is going to be more of an issue if you're boring a parallel tunnel rather than a cross tunnel. Furthermore, all of the access points now have to go deeper to reach the new tunnel, which could introduce passenger circulation issues. It will also have passenger circulation issues during construction. Maintaining access to existing infrastructure during construction is complex after all.
- stcredzero 8y ago
  Digging a new tunnel immediately underneath an old tunnel is going to introduce different stresses on the old tunnel So then dig the new tunnel beside it. Maintaining access to existing infrastructure during construction is complex after all. For many complex industries, there is innovation and cost reduction. Digging larger parallel tunnels is something that the industry should be making easier and cheaper, leveraging the existing infrastructure. The mindset that "tunneling is expensive" is exactly the kind of self-fulfilling prophecy which prevents such progress.
  - jcranmer 8y ago