09-09-2011, 08:22 AM
Hort,
Something to think about. The human element is involved in signalled, degraded signalled and pilot moves including communication. Personally, I'd suggest whilst the highest risk is communication based as you suggested, it is the abnormal method of working, i.e. human factors, that is the true hazard. Specifically, the communication between pilot and signaller is mitigated by the pilot acting as a token/annetts key and trains cannot move without them! Three competent people (signaller, pilot, driver) ensuring safe movement of trains rather than just two in degraded signalling. Whereas the degraded mode, i.e. use of non-normal routes, especially in complex P&C, has the potential to cause greater confusion.
There is an increased SPAD risk especially for trains not expected to stop there normally BUT there are mitigation methods for that as well. An example is stopping the trains at the previous block and reminding them they will stop at the next box.
Pilot working slows traffic down (dependant upon levels) and has the disadvantage of one pilot who would need to travel if two trains needs to go in the same direction sequentially without an opposite direction move.
Therefore, there is a suggestion that pilot operation is not more risky but is operationally less than desirable. Remember, risk is a combination of hazard assessed against frequency and severity. Risk can always be mitigated but is the mitigation itself tolerable (complexity, cost, effort) versus the decrease of the risk (read Wikipedia: ALARP), i.e. cost:benefit ration.
Well done though.
Jerry
Something to think about. The human element is involved in signalled, degraded signalled and pilot moves including communication. Personally, I'd suggest whilst the highest risk is communication based as you suggested, it is the abnormal method of working, i.e. human factors, that is the true hazard. Specifically, the communication between pilot and signaller is mitigated by the pilot acting as a token/annetts key and trains cannot move without them! Three competent people (signaller, pilot, driver) ensuring safe movement of trains rather than just two in degraded signalling. Whereas the degraded mode, i.e. use of non-normal routes, especially in complex P&C, has the potential to cause greater confusion.
There is an increased SPAD risk especially for trains not expected to stop there normally BUT there are mitigation methods for that as well. An example is stopping the trains at the previous block and reminding them they will stop at the next box.
Pilot working slows traffic down (dependant upon levels) and has the disadvantage of one pilot who would need to travel if two trains needs to go in the same direction sequentially without an opposite direction move.
Therefore, there is a suggestion that pilot operation is not more risky but is operationally less than desirable. Remember, risk is a combination of hazard assessed against frequency and severity. Risk can always be mitigated but is the mitigation itself tolerable (complexity, cost, effort) versus the decrease of the risk (read Wikipedia: ALARP), i.e. cost:benefit ration.
Well done though.
Jerry
Le coureur