4 ms·

In a nutshell, for added stability back when it was thought that BART tracks would follow the lower deck of the Golden Gate Bridge: > Michael Healy, a BART his

In a nutshell, for added stability back when it was thought that BART tracks would follow the lower deck of the Golden Gate Bridge: > Michael Healy, a BART historian and the former BART Director of Public Affairs, believes the use of the broad gauge “goes back to when BART was planned to go across the lower deck of the Golden Gate Bridge,” he told BART recently. > “High winds coming through the gate would have required more stability for the aluminum-shelled cars. Thus, the wide gauge, as I recall,” he said. Why that particular gauge (five-feet-six-inches) and not the more widely-used standard ( four-feet-and-eight-and-a-half inches)? > The pamphlet does not specify why only the wide gauge of five-feet-six inches was tested and not others. One possibility is that the broad gauge was among the more widely used gauges in other countries. Another theory is that complex calculations were required, thus limiting alternatives that could be practically evaluated at the time.

dheera 4y ago
I mean, if your train car has a width W, why not also make the track gauge also W? That would maximize stability, and you already need the footprint of W cleared and leveled anyway so you might as well just set it at W and not risk anything.
- scraptor 4y ago
  Because there's a only slightly smaller standard track gauge that's well understood and has evolved over 150 years, has suppliers available for your every need, and can interoperate with standard rolling stock. Seeing how BART turned out they would have done well to stick to more standard approaches instead of badly reinventing the basics.
  - ant6n 4y ago
    But that’s where the idea comes from that BART is somewhat of a consultant fee driven conspiracy. If u design a bunch of unnecessary engineering from scratch, it’s easier to create more costs and funnel the spending to your friends.
- samtho 4y ago
  Standards exist for a reason. Almost all rolling stock in the US and much of the world is set to this gauge because it was good compromise. By using a nonstandard gauge, they have forever limited themselves to completely custom rolling stock and related components. The decision to use wide gauge, however it was it was decided, contributed to BART becoming one of the most expensive rail systems in the US to maintain.
  - twobitshifter 4y ago
    If you look, you’ll be unable to find a metro system in the US that does not have custom rolling stock. BART has unique requirements, but you’ll see that everywhere you look.
    - inferiorhuman 4y ago
      Most metro systems have more in common with each other than with BART. Nearly everything on BART is one off. For instance Muni has a bunch of small radius 90° turns so they need to have articulated cars with relatively narrow front/rear ends. So yeah that's custom, and a relatively minor inconvenience at service/repair time. Compare that to BART where a power surge damaged thyristors on fifty(!) cars and BART struggled to find replacements. Other metro systems use thyristors, but most other systems run 600–800 VDC. On any other system you could probably source from a variety of vendors or operators. BART runs 1000 VDC and thus needs expensive, unique, hard to find, thyristors. Anyways for a hot moment back in the 30s rail operators standardized on a train design. It's totally doable. https://en.wikipedia.org/wiki/PCC_streetcar https://en.wikipedia.org/wiki/PCC_streetcar
  - dheera 4y ago
    It doesn't seem like the world has much of a standard though, as much as they have a term "standard gauge". I was on a train from China to Mongolia where they lifted each train car, one by one, passengers inside and everything, to change the boogies for a different track gauge so the train could continue. At the France/Spain border my train changed its gauge mechanically on-the-fly. The tech is there, it's probably some stupid patents that prevent the rest of the world from having this efficiency.

dheera 4y ago

I mean, if your train car has a width W, why not also make the track gauge also W? That would maximize stability, and you already need the footprint of W cleared and leveled anyway so you might as well just set it at W and not risk anything.

scraptor 4y ago
Because there's a only slightly smaller standard track gauge that's well understood and has evolved over 150 years, has suppliers available for your every need, and can interoperate with standard rolling stock. Seeing how BART turned out they would have done well to stick to more standard approaches instead of badly reinventing the basics.
- ant6n 4y ago
  But that’s where the idea comes from that BART is somewhat of a consultant fee driven conspiracy. If u design a bunch of unnecessary engineering from scratch, it’s easier to create more costs and funnel the spending to your friends.
samtho 4y ago
Standards exist for a reason. Almost all rolling stock in the US and much of the world is set to this gauge because it was good compromise. By using a nonstandard gauge, they have forever limited themselves to completely custom rolling stock and related components. The decision to use wide gauge, however it was it was decided, contributed to BART becoming one of the most expensive rail systems in the US to maintain.
- twobitshifter 4y ago
  If you look, you’ll be unable to find a metro system in the US that does not have custom rolling stock. BART has unique requirements, but you’ll see that everywhere you look.
  - inferiorhuman 4y ago
    Most metro systems have more in common with each other than with BART. Nearly everything on BART is one off. For instance Muni has a bunch of small radius 90° turns so they need to have articulated cars with relatively narrow front/rear ends. So yeah that's custom, and a relatively minor inconvenience at service/repair time. Compare that to BART where a power surge damaged thyristors on fifty(!) cars and BART struggled to find replacements. Other metro systems use thyristors, but most other systems run 600–800 VDC. On any other system you could probably source from a variety of vendors or operators. BART runs 1000 VDC and thus needs expensive, unique, hard to find, thyristors. Anyways for a hot moment back in the 30s rail operators standardized on a train design. It's totally doable. https://en.wikipedia.org/wiki/PCC_streetcar https://en.wikipedia.org/wiki/PCC_streetcar
- dheera 4y ago
  It doesn't seem like the world has much of a standard though, as much as they have a term "standard gauge". I was on a train from China to Mongolia where they lifted each train car, one by one, passengers inside and everything, to change the boogies for a different track gauge so the train could continue. At the France/Spain border my train changed its gauge mechanically on-the-fly. The tech is there, it's probably some stupid patents that prevent the rest of the world from having this efficiency.