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ATP - peternrz - 30-08-2010
Hi PJW,
How is failure of train borne equipment dealt with in order to continue running trains whilst using an ATP system in the case of both intermittent and continous systems?
RE: ATP - PJW - 31-08-2010
(30-08-2010, 10:27 PM)peternrz Wrote: Hi PJW,
How is failure of train borne equipment dealt with in order to continue running trains whilst using an ATP system in the case of both intermittent and continous systems?
Depends what you mean by "failure".
If you mean a sudden catastrophic failure that cannot be solved by re-booting the system, then there is a means of the driver isolating the system so that the train brakes can be released. The railway's procedures are then followed but typically this might mean manual driving (let us assume that the ATP is a pure supplement to conventional lineside signals) as an "unfitted" train until it is "reasonable" to take the train out of service.
Depending on the rules for the specific line this may be the very first station at which all the passengers can be evacuated, it may be the first main station at which the train was booked to call anyway, it could perhaps be the end of that train's scheduled journey or (and this is unlikely) the unit's entire diagram for the day.
Read the Southall Report- although that actually was relevant to AWS; ironically the ATP in the train would have been operative but driver not trained and competent to use it so it wa running around with it isolated- this would not be permitted now.
Perhaps there could be other possibilities; last week a train for Newcastle coming into Reading from Guildford had a defective windscreen wiper affecting the front cab, so the passenegers had a slight diversion to the south around one chord of a triangle to Reading West station, the driver changed ends and then the train continued north around the west curve to resume the scheduled route west but with the driver utilising the other cab; where the track layout permits this could be used as an alternative to terminating the train, depending of course precisely the nature of the fault and how independent the two cab fitments are.
I don't think there is a distinction worth making in this context between continuous and intermittent systems- indeed taking the GW ATP there are sections where it is effectively continuous and others where it is intermittent- this is fundamentally a feature of the TRACKSIDE, yet your question referred to the ON BOARD. Be aware that i an intermittent system the PROTECTION is normally continuous; it is just that the status is only intermittently updated (generally as trains pass signals) rather than anywhere on their journey (between signals).
Obviously if you were meaning continuous and intermittent FAULTS then my answere may have been slightly diffferent as I think that the occasional inappropriate intervention by ATP would be more tolerated to allow the train to complete its booked journey than doing so with system completely isolated, thus avoiding need to turf passengers off at an intermediate station having few facilities and a sparse train service.