Hi Andy, you quote 10^14 for track circuits. Do you have reference for that figure please. Just been in an argument with other people over removal of track circuits vs. unproven GPS location system. This would be helpful. Thanks. If you don't mind I will join the conversation below.
Andy Millar:
Hi James,
I would just add a couple of caveats to your thoughts.
Firstly, remember the level of safety you are trying to achieve. To satisfy the public acceptance of risk on the railways you need an unsafe equipment failure rate of (typically) one failure in 10^14 years. (As an example, this is what track circuits achieve.) This does not come cheaply - particularly in low volume equipment.
Secondly, unfortunately it is not going to be practical for any "line of sight" system (however automated) to brake a 200 tonne train travelling at 150mph on metal rails in its viewable distance - wheelspin detection is already in place, but to quote a famous engineer "ye canna change the laws of physics captain!" Hence the "block" system to keep trains a safe distance apart, and a huge amount of other activities to keep other obstructions off the line - which is why level crossings are such a problem.
I certainly agree that there need to be lessons shared between autonomous rail and autonomous road, however I suspect the learning process might go the other way to the one you expect. Road vehicles have traditionally been based on safety arguments based around driver intervention, with fully autonomous vehicles this argument changes completely. The rail industry has over 100 years experience of considering safety arguments based around automatic control methods, and there will be a lot of learning of how to approach a safety decision that will be transferrable. (Incidentally, ditto from aviation.) A key part of this - and I suspect, a particular area of upcoming controversy - is going to be transparency. Rail supply companies have to be fully transparent in their IP, no secrets are allowed about how their safety is assured. Once the risks of fully autonomous vehicles become fully apparent then the automotive industry, where extreme product secrecy is consider vital to staying ahead, could be in for a bit of a shock.
Interesting discussion, thank you. You might like to look at the UK "Digital Railway" project digitalrailway.co.uk to see what is coming along for the UK. Cash permitting there are some big changes ahead!
Andy
Hi Andy, you quote 10^14 for track circuits. Do you have reference for that figure please. Just been in an argument with other people over removal of track circuits vs. unproven GPS location system. This would be helpful. Thanks. If you don't mind I will join the conversation below.
Andy Millar:
Hi James,
I would just add a couple of caveats to your thoughts.
Firstly, remember the level of safety you are trying to achieve. To satisfy the public acceptance of risk on the railways you need an unsafe equipment failure rate of (typically) one failure in 10^14 years. (As an example, this is what track circuits achieve.) This does not come cheaply - particularly in low volume equipment.
Secondly, unfortunately it is not going to be practical for any "line of sight" system (however automated) to brake a 200 tonne train travelling at 150mph on metal rails in its viewable distance - wheelspin detection is already in place, but to quote a famous engineer "ye canna change the laws of physics captain!" Hence the "block" system to keep trains a safe distance apart, and a huge amount of other activities to keep other obstructions off the line - which is why level crossings are such a problem.
I certainly agree that there need to be lessons shared between autonomous rail and autonomous road, however I suspect the learning process might go the other way to the one you expect. Road vehicles have traditionally been based on safety arguments based around driver intervention, with fully autonomous vehicles this argument changes completely. The rail industry has over 100 years experience of considering safety arguments based around automatic control methods, and there will be a lot of learning of how to approach a safety decision that will be transferrable. (Incidentally, ditto from aviation.) A key part of this - and I suspect, a particular area of upcoming controversy - is going to be transparency. Rail supply companies have to be fully transparent in their IP, no secrets are allowed about how their safety is assured. Once the risks of fully autonomous vehicles become fully apparent then the automotive industry, where extreme product secrecy is consider vital to staying ahead, could be in for a bit of a shock.
Interesting discussion, thank you. You might like to look at the UK "Digital Railway" project digitalrailway.co.uk to see what is coming along for the UK. Cash permitting there are some big changes ahead!
Andy
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