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You don't even need to slow down, in some cases. I was watching a video[0] about how shinkansen trains are serviced each day, and noticed at one point[2] when t

by ok_dad 4y ago

You don't even need to slow down, in some cases. I was watching a video[0] about how shinkansen trains are serviced each day, and noticed at one point[2] when the workers are ready to clean the top of the train they do a "point and call"[1] routine at a gate. Now, I am not exactly sure what the purpose is for that, because there isn't much context in the video, but I am logically assuming that they are checking that the train's overhead wires are depowered, and the gate probably only allows itself to be opened when that is the case. Even if that's not the exact reason here, I could imagine a test facility where you had occupancy sensors inside and a lockout gate that operated in this fashion, and wouldn't allow a human to be inside the room while pressure was increased in the test valve. I honestly don't get the cowboy attitude in here, we can progress to space quickly AND safely. [0]: https://www.youtube.com/watch?v=ieRwRS0VUUM https://www.youtube.com/watch?v=ieRwRS0VUUM [1]: https://en.wikipedia.org/wiki/Pointing_and_calling https://en.wikipedia.org/wiki/Pointing_and_calling [2]: https://youtu.be/ieRwRS0VUUM?t=578 https://youtu.be/ieRwRS0VUUM?t=578

lolc 4y ago
There's a section in the article relating the procedure of spraying the pressurized engine with a liquid to check for bubbles. The bubbles indicate leaks. Humans go close to the engine to check for leaks. They can point and call all they want, it is inherently unsafe for them to be there. It is unclear to me how that procedure could be replaced and I won't dismiss it as cowboy attitude.
- Jtsummers 4y ago
  It's SpaceX, sister company of Tesla. They can have a small bot that goes around spraying and many cameras and other sensors observing. And given they're looking for potentially very small leaks from a pressurized system you wouldn't want a person physically present when the leak is discovered at high pressure anyways, not unless you want to see the effect of a very narrow high pressure stream hitting human skin (or a fast moving piece of hardware hitting their skull).
  - lolc 4y ago
    I'm sure if the tech were up to the task, they'd have a robot you could walk around with and look at things. But it'd need really good resolution and dynamic range paired with flexible and fine motor control to lean into an engine and look for tiny bubbles. This is a research field of its own. Not something they just have. For example: Humans improve their visual perception by lightly shifting their heads to avoid reflections, gauge shadows and mitigate obstructions. If the tech can't follow, you have an inferior solution. A solution where bubbles will be missed. Just staring at a screen is not the same. Even if you can tilt the camera.
- andrewaylett 4y ago
  The bubble test is not carried out at full pressure. That's the point: you find the leaks before blowing the engine up because you didn't spot a leak. The tag-out system could, for example, use a pressure relief valve. I suspect they even have one already when running the test, but if someone was in the wrong space when the relief valve wasn't in place then I assume they're not using it as a tag point.
wahern 4y ago
The Shinkansen services claim zero passenger fatalities (and close to zero passenger injuries, on account of a recent mishap). If you carefully parse the language of these claims, taking note to discount those ineptly rephrasing official claims, these statistics usually do not include workers. Here's a paper discussing how those trains are cleaned: https://siliconflatirons.org/wp-content/uploads/2018/04/Trouble-at-Tessei-Case.pdf https://siliconflatirons.org/wp-content/uploads/2018/04/Trou... Exhibit 10, page 11 shows the number of employee accidents for the years 2001-2005. No year had zero. 2004 and 2005 were as high as 18 employee accidents. Here's a fatality from just last year during tunnel construction for a maglev line: https://www.japantimes.co.jp/news/2021/10/29/national/jr-tunnel-death/ https://www.japantimes.co.jp/news/2021/10/29/national/jr-tun...
- ok_dad 4y ago
  Ok but I’m talking about one specific safety effort in regards to the article not the general safety record. I’m not saying everyone has to have zero accidents, but clearly there are things we can do that aren’t having some guy spray liquid on a pressurized valve.

by ok_dad 4y ago

lolc 4y ago

There's a section in the article relating the procedure of spraying the pressurized engine with a liquid to check for bubbles. The bubbles indicate leaks. Humans go close to the engine to check for leaks. They can point and call all they want, it is inherently unsafe for them to be there. It is unclear to me how that procedure could be replaced and I won't dismiss it as cowboy attitude.

Jtsummers 4y ago
It's SpaceX, sister company of Tesla. They can have a small bot that goes around spraying and many cameras and other sensors observing. And given they're looking for potentially very small leaks from a pressurized system you wouldn't want a person physically present when the leak is discovered at high pressure anyways, not unless you want to see the effect of a very narrow high pressure stream hitting human skin (or a fast moving piece of hardware hitting their skull).
- lolc 4y ago
  I'm sure if the tech were up to the task, they'd have a robot you could walk around with and look at things. But it'd need really good resolution and dynamic range paired with flexible and fine motor control to lean into an engine and look for tiny bubbles. This is a research field of its own. Not something they just have. For example: Humans improve their visual perception by lightly shifting their heads to avoid reflections, gauge shadows and mitigate obstructions. If the tech can't follow, you have an inferior solution. A solution where bubbles will be missed. Just staring at a screen is not the same. Even if you can tilt the camera.
andrewaylett 4y ago
The bubble test is not carried out at full pressure. That's the point: you find the leaks before blowing the engine up because you didn't spot a leak. The tag-out system could, for example, use a pressure relief valve. I suspect they even have one already when running the test, but if someone was in the wrong space when the relief valve wasn't in place then I assume they're not using it as a tag point.

wahern 4y ago

The Shinkansen services claim zero passenger fatalities (and close to zero passenger injuries, on account of a recent mishap). If you carefully parse the language of these claims, taking note to discount those ineptly rephrasing official claims, these statistics usually do not include workers. Here's a paper discussing how those trains are cleaned: https://siliconflatirons.org/wp-content/uploads/2018/04/Trouble-at-Tessei-Case.pdf https://siliconflatirons.org/wp-content/uploads/2018/04/Trou... Exhibit 10, page 11 shows the number of employee accidents for the years 2001-2005. No year had zero. 2004 and 2005 were as high as 18 employee accidents. Here's a fatality from just last year during tunnel construction for a maglev line: https://www.japantimes.co.jp/news/2021/10/29/national/jr-tunnel-death/ https://www.japantimes.co.jp/news/2021/10/29/national/jr-tun...

ok_dad 4y ago
Ok but I’m talking about one specific safety effort in regards to the article not the general safety record. I’m not saying everyone has to have zero accidents, but clearly there are things we can do that aren’t having some guy spray liquid on a pressurized valve.