4 ms·

As I understand it (and I am certainly not qualified in any regard with respect to this type of engineering) he is aiming to increase velocity by decreasing dia

As I understand it (and I am certainly not qualified in any regard with respect to this type of engineering) he is aiming to increase velocity by decreasing diameter (ie couple meter diameter vs 10m diameter) and then also looking at how they can ‘juice’ the machine using engineering magic

iamtheworstdev 7y ago
And I'm just going off of Wikipedia here on the Boring Company's page but apparently they modified a commercial borer to be 3x as fast as the original and are currently trying to manufacture a borer of their own design which they claim will be 10x faster.
- abduhl 7y ago
  The Boring Company took 2 years to go 6000 ft at 15’ diameter excavated. There are plenty of ways to slice and dice this number up but the short version is that this is not faster than how the original TBM performed (let alone 3x) - I know the guys that Elon bought the TBM from and the guys that those guys bought it from. As I’ve said in previous posts about this, TBM operation is not the limiting factor in building a tunnel. Permit acquisition and third parties are the longest part of tunneling projects by far.
bobthepanda 7y ago
The London Tube was built with a 3.58m diameter. Jubilee Line Extension had a 4.4m diameter, Crossrail will have 6.2m diameter. So the diameter reduction is not that much smaller, and it certainly isn’t the smallest attempted. The original Tube tunnels actually have several problems - the tight diameter means that air conditioning is basically an impossibility (no room for the equipment in vehicles and nowhere to output the heat), and it makes maintenance and emergency evacuation annoying and hazardous if you can’t have a walkway for people to walk alongside the trackway.
- robbiep 7y ago
  most of the original tunneling was done by hand, so i'm not sure if it's directly comparable. There was an interesting article regarding the heat transfer to the surrounding ground recently - [0] that i'm sure you'll find interesting if you haven't seen it before!
  - bobthepanda 7y ago
    Jubilee Line Extension was the '90s and Crossrail is opening soon, so those definitely weren't by hand! I have seen articles about it, as well as a recent proposal to use that heat for heating homes. But it just illustrates the (many) potential pitfalls of small diameter tunnels, because you really don't want your tunnel to become an oven after a few decades of heat generated from braking. Other pitfalls include: You need space for adequate ventilation. This is less of a problem with electric propulsion, but you do still need it for emergencies (like a fire). And then there's the issue of noise; if your vehicle is too small compared to the tunnel, then the air being forced out once you get to a larger space (like the outside or a station) creates loud noise. Japanese high speed rail trains have much stranger aerodynamic shapes than European ones because they built smaller diameter tunnels and this ended up causing noise issues at higher speeds.
- 420codebro 7y ago
  Also the lack of a meaningful buffer of air between the trains and the tunnel wall results in a lot of extra heat (convection) to be absorbed by the surrounding environment, making the underground more hot.

iamtheworstdev 7y ago

And I'm just going off of Wikipedia here on the Boring Company's page but apparently they modified a commercial borer to be 3x as fast as the original and are currently trying to manufacture a borer of their own design which they claim will be 10x faster.

abduhl 7y ago
The Boring Company took 2 years to go 6000 ft at 15’ diameter excavated. There are plenty of ways to slice and dice this number up but the short version is that this is not faster than how the original TBM performed (let alone 3x) - I know the guys that Elon bought the TBM from and the guys that those guys bought it from. As I’ve said in previous posts about this, TBM operation is not the limiting factor in building a tunnel. Permit acquisition and third parties are the longest part of tunneling projects by far.

bobthepanda 7y ago

The London Tube was built with a 3.58m diameter. Jubilee Line Extension had a 4.4m diameter, Crossrail will have 6.2m diameter. So the diameter reduction is not that much smaller, and it certainly isn’t the smallest attempted. The original Tube tunnels actually have several problems - the tight diameter means that air conditioning is basically an impossibility (no room for the equipment in vehicles and nowhere to output the heat), and it makes maintenance and emergency evacuation annoying and hazardous if you can’t have a walkway for people to walk alongside the trackway.

robbiep 7y ago
most of the original tunneling was done by hand, so i'm not sure if it's directly comparable. There was an interesting article regarding the heat transfer to the surrounding ground recently - [0] that i'm sure you'll find interesting if you haven't seen it before!
- bobthepanda 7y ago
  Jubilee Line Extension was the '90s and Crossrail is opening soon, so those definitely weren't by hand! I have seen articles about it, as well as a recent proposal to use that heat for heating homes. But it just illustrates the (many) potential pitfalls of small diameter tunnels, because you really don't want your tunnel to become an oven after a few decades of heat generated from braking. Other pitfalls include: You need space for adequate ventilation. This is less of a problem with electric propulsion, but you do still need it for emergencies (like a fire). And then there's the issue of noise; if your vehicle is too small compared to the tunnel, then the air being forced out once you get to a larger space (like the outside or a station) creates loud noise. Japanese high speed rail trains have much stranger aerodynamic shapes than European ones because they built smaller diameter tunnels and this ended up causing noise issues at higher speeds.
420codebro 7y ago
Also the lack of a meaningful buffer of air between the trains and the tunnel wall results in a lot of extra heat (convection) to be absorbed by the surrounding environment, making the underground more hot.