5 ms·

It's interesting that the biggest line item in the costing is not the tube, nor the capsules, nor the vacuum pumps, nor the solar panels, nor the land, but the

by alex-g 13y ago

It's interesting that the biggest line item in the costing is not the tube, nor the capsules, nor the vacuum pumps, nor the solar panels, nor the land, but the concrete pylons that support the tube - about two-fifths of the total. The pylons are planned to be 30m apart, making for about 25000 of them.

toomuchtodo 13y ago
But that's the beauty of it! You can make those pylons anywhere, truck them in, and install them in whatever order you want. It's construction....that scales up almost effortlessly.
- alex-g 13y ago
  I suppose that's true, though I don't know if that's a real difference compared to building other very long things that are the same all the way along, like roads and railways and the Great Wall of China. It's just fascinating to me that the most expensive thing (in aggregate) is also the "dumbest" part.
  - dlss 13y ago
    The most expensive thing in aggregate is the part which surely received the most attention when cost cutting. I think it makes perfect sense it's the dumbest part.
- TomGullen 13y ago
  Also much easier to maintain and replace
- RyJones 13y ago
  perhaps you can pour sections and truck those in, but there's no way in hell you're moving a precast that size on anything that doesn't float. For scale, you know those 4' by 4' by 8' blocks of cement you see all over the place, used for erosion control and the like? They're called ecology blocks, they're about $20 each FOB the cement plant. You want them shipped? A lowboy can carry two or four at a time without exceeding load limits. When I looked into buying a couple hundred, having them shipped about sixteen miles, it was going to cost hundreds per block to truck it out plus renting a crane to unload/place them. Those are tiny blocks with almost no rebar, no engineering, no preload, nothing.
  - yutyut 13y ago
    Ecology blocks: http://www.tworiverssandandgravel.com/wp-content/uploads/2010/04/ecology_blocks_imprinted.jpg http://www.tworiverssandandgravel.com/wp-content/uploads/201...
    - nkurz 13y ago
      They are also colloquially known as 'mafia blocks' for some reason...
  - HCIdivision17 13y ago
    While I certainly can't say anything for the economy of long distance shipping of giant concrete pylons, I can confirm they do get trucked around a lot in the Dallas area. The overpass ribs are basically hooked to a small truck attached to the cab with a small truck on the other far end. Again, dunno if it's feasible over long distance, but it's certainly done. (Though Texas has a certain affinity to overpasses that borders on the pathological, fun as they are to bike over...)
  - toomuchtodo 13y ago
    Pretty sure you can truck pylons if you can truck in precast bridge decks: https://www.google.com/search?q=precast+bridge+deck https://www.google.com/search?q=precast+bridge+deck
    - RyJones 13y ago
      Concrete is about two tons per yard. The legal limit on most trailers is about 20 tons (40,000 pounds, the trailer is about 40,000 for the legal limit of 80,000 pounds). So you can get about 10 yards of concrete in one go; you can use specialty trailers to get higher numbers, but even if you double it to 40 tons, that's still only 20 yards. a 4' x 4' x 8' ecology block is about five yards. So let's picture the pylon having a 4' x 4' base that sits on granite, requiring no foundation. The pylon is going to max out at 16 or 32 feet tall if we're required to stay within the load limits. furthermore, when you see those ribs moving around, they're moving around on interstates or state roads of solid construction. If there was an interstate running directly from San Francisco to Los Angeles along this route, we wouldn't be having the discussion. Building such a road to deliver precast sections is quite the endeavor. I stand by my original claim that these would need to be cast-in-place.
- jlgreco 13y ago
  You'd still have to pour the foundation in place though, right? Or can you make foundations off-site and then drive them into the ground?
adwf 13y ago
They don't seem to break down the labour costs of building the tube/pylons very well. In my experience watching big government projects, that's where the massive overages start coming in. It's easy to say that something will cost (eg.) $1bn if it's built in 2 years, but when most of that is labour and bureaucracy starts getting involved, the labour gets put on hold for a year or two whilst still getting paid. Suddenly the overall cost of the project has tripled without anything actually changing, except some bureaucrat sticking their oar in. Maybe I'm just cynical, but the labour costs seem to be one of the least well defined aspects of this proposal. It's easy enough to make it look cost effective compared to existing rail projects when you don't factor that in. Afterall do you really think that the HSV with two steel rails is costing $80bn+ because of the price of the components? Although I don't really know the specifics, I find it hard to believe that the rights of way cost that much either. It's usually down to contracting an entire company worth of engineers for 10-20 years that ramps up the costs.

by alex-g 13y ago

toomuchtodo 13y ago

But that's the beauty of it! You can make those pylons anywhere, truck them in, and install them in whatever order you want. It's construction....that scales up almost effortlessly.

alex-g 13y ago
I suppose that's true, though I don't know if that's a real difference compared to building other very long things that are the same all the way along, like roads and railways and the Great Wall of China. It's just fascinating to me that the most expensive thing (in aggregate) is also the "dumbest" part.
- dlss 13y ago
  The most expensive thing in aggregate is the part which surely received the most attention when cost cutting. I think it makes perfect sense it's the dumbest part.
TomGullen 13y ago
Also much easier to maintain and replace
RyJones 13y ago
perhaps you can pour sections and truck those in, but there's no way in hell you're moving a precast that size on anything that doesn't float. For scale, you know those 4' by 4' by 8' blocks of cement you see all over the place, used for erosion control and the like? They're called ecology blocks, they're about $20 each FOB the cement plant. You want them shipped? A lowboy can carry two or four at a time without exceeding load limits. When I looked into buying a couple hundred, having them shipped about sixteen miles, it was going to cost hundreds per block to truck it out plus renting a crane to unload/place them. Those are tiny blocks with almost no rebar, no engineering, no preload, nothing.
- yutyut 13y ago
  Ecology blocks: http://www.tworiverssandandgravel.com/wp-content/uploads/2010/04/ecology_blocks_imprinted.jpg http://www.tworiverssandandgravel.com/wp-content/uploads/201...
  - nkurz 13y ago
    They are also colloquially known as 'mafia blocks' for some reason...
- HCIdivision17 13y ago
  While I certainly can't say anything for the economy of long distance shipping of giant concrete pylons, I can confirm they do get trucked around a lot in the Dallas area. The overpass ribs are basically hooked to a small truck attached to the cab with a small truck on the other far end. Again, dunno if it's feasible over long distance, but it's certainly done. (Though Texas has a certain affinity to overpasses that borders on the pathological, fun as they are to bike over...)
- toomuchtodo 13y ago
  Pretty sure you can truck pylons if you can truck in precast bridge decks: https://www.google.com/search?q=precast+bridge+deck https://www.google.com/search?q=precast+bridge+deck
  - RyJones 13y ago
    Concrete is about two tons per yard. The legal limit on most trailers is about 20 tons (40,000 pounds, the trailer is about 40,000 for the legal limit of 80,000 pounds). So you can get about 10 yards of concrete in one go; you can use specialty trailers to get higher numbers, but even if you double it to 40 tons, that's still only 20 yards. a 4' x 4' x 8' ecology block is about five yards. So let's picture the pylon having a 4' x 4' base that sits on granite, requiring no foundation. The pylon is going to max out at 16 or 32 feet tall if we're required to stay within the load limits. furthermore, when you see those ribs moving around, they're moving around on interstates or state roads of solid construction. If there was an interstate running directly from San Francisco to Los Angeles along this route, we wouldn't be having the discussion. Building such a road to deliver precast sections is quite the endeavor. I stand by my original claim that these would need to be cast-in-place.
jlgreco 13y ago
You'd still have to pour the foundation in place though, right? Or can you make foundations off-site and then drive them into the ground?

adwf 13y ago

They don't seem to break down the labour costs of building the tube/pylons very well. In my experience watching big government projects, that's where the massive overages start coming in. It's easy to say that something will cost (eg.) $1bn if it's built in 2 years, but when most of that is labour and bureaucracy starts getting involved, the labour gets put on hold for a year or two whilst still getting paid. Suddenly the overall cost of the project has tripled without anything actually changing, except some bureaucrat sticking their oar in. Maybe I'm just cynical, but the labour costs seem to be one of the least well defined aspects of this proposal. It's easy enough to make it look cost effective compared to existing rail projects when you don't factor that in. Afterall do you really think that the HSV with two steel rails is costing $80bn+ because of the price of the components? Although I don't really know the specifics, I find it hard to believe that the rights of way cost that much either. It's usually down to contracting an entire company worth of engineers for 10-20 years that ramps up the costs.