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You think the rail industry understands what safety means? Trains have literally one degree of freedom in their controls - speed up and slow down. In spite of

by maxcan 9y ago

You think the rail industry understands what safety means? Trains have literally one degree of freedom in their controls - speed up and slow down. In spite of the simplicity we still see high fatality train crashes with regularity. Some how sticking people in a paper thin aluminum tube 6 miles up going 600mph can be done with zero fatalities but we can't get trains to stop killing people. I'm ranting here, but you're on an undeservedly high horse.

crocal 9y ago
No problem at all, I was half expecting such reaction. http://www.uitp.org/sites/default/files/Metro%20automation%20-%20facts%20and%20figures.pdf http://www.uitp.org/sites/default/files/Metro%20automation%2... There has been 1 accident in 30 years attributed to driverless rail mass transit control system, despite millions of kilometers travelled and a constant worldwide growth. Yes, rail has understood what driverless safety means. You may call it a high horse but driverless /is/ a high horse. That's my point. In a way, your comment confirms this success. You think it is easy because you are used to it at an instinctive level. And that is the goal, precisely. But it is not as simple as what you imagine. For instance, trains have multiple degree of freedoms. As an illustration, train builders calculate carefully the dynamic enveloppe of the cars (e.g. its worst lateral deformation due to bogie flexibility) and check against the tunnel walls geometry. http://www.railsystem.net/structure-gauge-and-kinematic-envelope/ http://www.railsystem.net/structure-gauge-and-kinematic-enve...
- kerbalspacepro 9y ago
  Are we talking about metros or trains? Metros are built out of the way. They shouldn't kill people because there are a few stations of track that they can kill people. The second you put the train in the open air where other people are, where weather is, where nature is, those things kill people on the regular. Get out of your tunnel, and suddenly your "success" has nothing to do with the control system.
  - crocal 9y ago
    Metros are the only driverless systems in mass transit so far. There are some ongoing projects for driverless freight but I consider that it is not relevant to this particular discussion. I don't want to sound obnoxious but driverless metros routinely operate in the open air :). Tunnels are not a mandatory condition for such systems. They manage strong winds, strong rains with reduced adhesion conditions, etc. They manage the possibility for people or non-protected trains to intrude on the track. A lot of brain was put into automating decisions related to fire scenarios or emergency evacuations. Metro lines like Paris line 1 are extremely busy. There are plenty of ways to kill people, yet they don't. Just the "stuck hand-bag" scenario is a nightmare to manage. Yet. A driverless system is truly a massive piece of software. You guys should come in the tunnels and have fun with us!
  - threadwhisperer 9y ago
    > Metros are built out of the way. They shouldn't kill people because there are a few stations of track that they can kill people. This is demonstrably false. There are many metro systems with tracks on viaducts and at-grade (e.g. "open air"), with GoA 4 control systems. These systems can and do detect objects on the track. They also deal with severe weather (heavy thunderstorms, snow, etc). I think you're discounting the experience of delivering railway systems without considering lessons that could be learned in deploying them, and applying that to self-driving cars.
- maxcan 9y ago
  Fair point, I guess I was referring more to this comment: > I don't think the majority understands what safety means in mass transportation. And inferring that you meant that rail understands safety, generally, better than any other mode of transportation which I took issue with. I believe you 100% when you say that only one accident in 30 years ahas been attributed to driverless trains. What I find horrifying about rail is how simple PTC should be: "am I exceeding the maximum speed for this stretch of rail? is there a train in front of me? if yes to either, slow down" and yet Amtrak says it will take billions of dollars and decades to install. I'm thinking of accidents like the NE Corridor derailment in 2015.
  - ricardobeat 9y ago
    You're again confirming the opposite: > the derailment was caused by the train's engineer (driver) becoming distracted by other radio transmissions and losing situational awareness, and said that it would have been prevented by positive train control, a computerized speed-limiting system
    - maxcan 9y ago
      I know that was the cause. I'm lamenting that the rail system has been unable to deploy PTC because of the cost, which, as a nonprofessional, seems astronomical for what should be a simple system. Remember, I was initially referring to rail's approach to safety generally, not just in the context of automation.
  - crocal 9y ago
    I can really understand your frustration on PTC. PTC is a problem of ROI for operators. The incentive is apparently not so great, so it will take decades. Also, and this is frequent in rail, any complicated solution that will leverage the existing infrastructure will be explored, further entangling the situation. In more controlled economies, the state has enforced for long the technology to be used. [1] Some may say it is a case where free market cannot be trusted to take the correct decisions. It is a societal debate, no longer an engineering topic. [2] [1] Not too bad: https://en.m.wikipedia.org/wiki/Positive_train_control https://en.m.wikipedia.org/wiki/Positive_train_control [2] https://en.m.wikipedia.org/wiki/Rail_Safety_Improvement_Act_of_2008 https://en.m.wikipedia.org/wiki/Rail_Safety_Improvement_Act_...

by maxcan 9y ago

crocal 9y ago

No problem at all, I was half expecting such reaction. http://www.uitp.org/sites/default/files/Metro%20automation%20-%20facts%20and%20figures.pdf http://www.uitp.org/sites/default/files/Metro%20automation%2... There has been 1 accident in 30 years attributed to driverless rail mass transit control system, despite millions of kilometers travelled and a constant worldwide growth. Yes, rail has understood what driverless safety means. You may call it a high horse but driverless /is/ a high horse. That's my point. In a way, your comment confirms this success. You think it is easy because you are used to it at an instinctive level. And that is the goal, precisely. But it is not as simple as what you imagine. For instance, trains have multiple degree of freedoms. As an illustration, train builders calculate carefully the dynamic enveloppe of the cars (e.g. its worst lateral deformation due to bogie flexibility) and check against the tunnel walls geometry. http://www.railsystem.net/structure-gauge-and-kinematic-envelope/ http://www.railsystem.net/structure-gauge-and-kinematic-enve...

kerbalspacepro 9y ago
Are we talking about metros or trains? Metros are built out of the way. They shouldn't kill people because there are a few stations of track that they can kill people. The second you put the train in the open air where other people are, where weather is, where nature is, those things kill people on the regular. Get out of your tunnel, and suddenly your "success" has nothing to do with the control system.
- crocal 9y ago
  Metros are the only driverless systems in mass transit so far. There are some ongoing projects for driverless freight but I consider that it is not relevant to this particular discussion. I don't want to sound obnoxious but driverless metros routinely operate in the open air :). Tunnels are not a mandatory condition for such systems. They manage strong winds, strong rains with reduced adhesion conditions, etc. They manage the possibility for people or non-protected trains to intrude on the track. A lot of brain was put into automating decisions related to fire scenarios or emergency evacuations. Metro lines like Paris line 1 are extremely busy. There are plenty of ways to kill people, yet they don't. Just the "stuck hand-bag" scenario is a nightmare to manage. Yet. A driverless system is truly a massive piece of software. You guys should come in the tunnels and have fun with us!
- threadwhisperer 9y ago
  > Metros are built out of the way. They shouldn't kill people because there are a few stations of track that they can kill people. This is demonstrably false. There are many metro systems with tracks on viaducts and at-grade (e.g. "open air"), with GoA 4 control systems. These systems can and do detect objects on the track. They also deal with severe weather (heavy thunderstorms, snow, etc). I think you're discounting the experience of delivering railway systems without considering lessons that could be learned in deploying them, and applying that to self-driving cars.
maxcan 9y ago
Fair point, I guess I was referring more to this comment: > I don't think the majority understands what safety means in mass transportation. And inferring that you meant that rail understands safety, generally, better than any other mode of transportation which I took issue with. I believe you 100% when you say that only one accident in 30 years ahas been attributed to driverless trains. What I find horrifying about rail is how simple PTC should be: "am I exceeding the maximum speed for this stretch of rail? is there a train in front of me? if yes to either, slow down" and yet Amtrak says it will take billions of dollars and decades to install. I'm thinking of accidents like the NE Corridor derailment in 2015.
- ricardobeat 9y ago
  You're again confirming the opposite: > the derailment was caused by the train's engineer (driver) becoming distracted by other radio transmissions and losing situational awareness, and said that it would have been prevented by positive train control, a computerized speed-limiting system
  - maxcan 9y ago
    I know that was the cause. I'm lamenting that the rail system has been unable to deploy PTC because of the cost, which, as a nonprofessional, seems astronomical for what should be a simple system. Remember, I was initially referring to rail's approach to safety generally, not just in the context of automation.
- crocal 9y ago
  I can really understand your frustration on PTC. PTC is a problem of ROI for operators. The incentive is apparently not so great, so it will take decades. Also, and this is frequent in rail, any complicated solution that will leverage the existing infrastructure will be explored, further entangling the situation. In more controlled economies, the state has enforced for long the technology to be used. [1] Some may say it is a case where free market cannot be trusted to take the correct decisions. It is a societal debate, no longer an engineering topic. [2] [1] Not too bad: https://en.m.wikipedia.org/wiki/Positive_train_control https://en.m.wikipedia.org/wiki/Positive_train_control [2] https://en.m.wikipedia.org/wiki/Rail_Safety_Improvement_Act_of_2008 https://en.m.wikipedia.org/wiki/Rail_Safety_Improvement_Act_...