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Driverless Trains

The March 2017 Issue of E&T carries several articles about driverless cars but why haven't we got driverless mainline trains?


The technical 'problem' should be far simpler to solve than for a road vehicle. The position on the 'road' can be predicted and determined easily with precision. There is essentially no collision problem to solve, that has been done with the existing signalling system.


There is no need for communication with the train, no need for additional infrastructure. All that is needed is to observe and act on the existing fixed signals.


Of course such a basic system can be improved upon to produce a 'super driver' capable of reacting to unplanned obstructions, greasy rails etc.


The human driver is perhaps the last link to be made 'fail-safe' in the railway safety regime. Our efforts to 'improve' the driver-train interface have probably added new problems. Regular signal spacings, standard aspects and driver alerts must surely increase the boredom and inattention factor. An example of this was the Shap Roll-back in August 2010 where a driver correctly observed adverse signals, came to a stop, then allowed the train to roll-back, acknowledging the retreating adverse signals on the way, until the train exceeded 50 mph. Presumably he was half asleep?


I suspect the real 'problem' is a social one, it will be a tragedy if we can't solve that one.

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  • 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

Reply
  • 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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