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Post by Deleted on Oct 17, 2006 9:07:56 GMT
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Post by Deleted on Oct 17, 2006 22:27:39 GMT
This accident is quite concerning, given that the trains are brand new (made by CAF), and the line is relatively modern (opened in 1980).
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Post by Deleted on Oct 18, 2006 0:09:25 GMT
No tripcocks? Or a "simple" case of signal failure? :/ A very sad event indeed.
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Post by Deleted on Oct 18, 2006 10:25:46 GMT
Tripcocks are a bit oldfashioned. I expect a modern system like Rome to have Automatic Train Protection, pretty standard stuff nowadays. I guess we'll hear the cause in a few weeks.
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Post by Deleted on Oct 18, 2006 21:02:15 GMT
tripcocks may be oldfashioned, but very reliable and failsafe. But you are the odd fella who likes the 92ts so must find ATP the best thing for trains now.
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Post by Deleted on Oct 18, 2006 21:09:44 GMT
tripcocks may be oldfashioned, but very reliable and failsafe. Nothing is 100% failsafe. On the Toronto subway a speeding trains tripcock missed a raised trainstop on a curve and thus failed to stop the train crashing into the train in front. An inquiry has started into the Rome crash. There is a lot of evidence from witnesses to suggest that the train ran through a red light. However, why the train wasn't stopped by the ATP is yet unknown. |
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Post by Deleted on Oct 18, 2006 21:22:31 GMT
;D
I know tripcocks are pretty reliable and safe. I just don't expect an underground system that was built almost a century later than ours with probably the whole ATO/ATP (perhaps moving block signalling) circuitry installed from the day it opened to still use a thing like tripcocks.
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Post by Dmitri on Oct 19, 2006 12:02:59 GMT
An unconfirmed assumption is that driver of the second train was passing a home signal in danger under authority, but went too fast after passing the red light (25-30 km/h instead of allowed 15 km/h).
BTW, the most reliable setup is "tripcock + ATS/ATP". |
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prjb
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Post by prjb on Oct 19, 2006 19:38:31 GMT
Tripcocks/Trainstops are no longer considered to be, from a risk point of view, 'As Low As Reasonably Practacle' (ALARP). Any new system or any upgrade to an existing system is expected to utilise modern signalling systems. Any rail operator that failed to implement such systems at time of build or upgrade would, in all likelyhood, have their safety case thrown out.
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Post by agoodcuppa on Oct 19, 2006 20:35:23 GMT
Any new system or any upgrade to an existing system is expected to utilise modern signalling systems. Is that to suggest that an new installation would be expected to use computer based equipment rather than a nice simple rising/falling arm fixed to the sleeper ends engaging with an arm on the leading bogie of the train that when knocked back by making forcible contact with the first arm opens a valve causing an emergency application? |
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Post by Deleted on Oct 19, 2006 22:08:37 GMT
Any new system or any upgrade to an existing system is expected to utilise modern signalling systems. Is that to suggest that an new installation would be expected to use computer based equipment rather than a nice simple rising/falling arm fixed to the sleeper ends engaging with an arm on the leading bogie of the train that when knocked back by making forcible contact with the first arm opens a valve causing an emergency application? Train stops are not quite that simple! Conventional tripcock signalling requires all sorts of maintenance heavy equipment and componants including air mains, trainstops, track circuits, relays etc etc. Modern communication based train control (CBTC) signalling requires some computers, axle counters, and radio transmitters and receivers (the latter of which can also be used for other useful things such as live CCTV relay). Modern CBTC systems have no moving parts! The cost effectiveness and reliability of a well implemented modern CBTC system is much better than conventional signalling according to many sources. By the way, the Rome Metro signalling system is as far as I'm aware an Alstom designed system, using coded track circuits (like on the Central Line). I don't know if the system uses ATO/ATP, or just ATP, but reports suggest that the train in the incident was being driven manually at the time of the collision. As I've mentioned in previous threads, there has only ever been one fatal metro crash caused by a train being driven automatically (in Washington), and that was in very poor adhesion conditions when the ATO system 1) should not have been used, and 2) defaulted to a higher performance setting after a station overrun. |
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Post by bwhughes on Oct 20, 2006 21:58:06 GMT
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Post by bwhughes on Oct 20, 2006 21:59:30 GMT
Does anyone know if the circumstances were similar to what caused the Metro accident in Valencia earlier this year?
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prjb
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Post by prjb on Oct 20, 2006 23:31:48 GMT
Unusually for me, I am going to go off topic for one second!
I'm really going to miss stephenk, he makes my arguements for me but in such an eloquent fashion! ;D
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Post by Deleted on Oct 22, 2006 15:20:53 GMT
I don't give a damn what the HSE say; the good old-fashioned trip-cock should really be used alongside the computer equivalent. If the computer crashes, the trip-cock could physically prevent a disaster.  Sorry, but you are obviously ill educated on the subject of modern signalling. Please read my above post about the excellent safety record of computer based signalling, and you will see that tripcocks are not needed with computer based signalling. If the on-board computer crashes or malfunctioned, the train will do an emergency stop, not crash into the train ahead! Going by the available evidence, it looks like the Rome crash was once again caused by human error, not by modern technology. |
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Post by Deleted on Oct 22, 2006 15:21:21 GMT
Unusually for me, I am going to go off topic for one second! I'm really going to miss stephenk, he makes my arguements for me but in such an eloquent fashion! ;D I'm still here, but only for 24hours! |
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Post by Deleted on Oct 23, 2006 11:22:49 GMT
Tripcocks/Trainstops are no longer considered to be, from a risk point of view, 'As Low As Reasonably Practacle' (ALARP). Any new system or any upgrade to an existing system is expected to utilise modern signalling systems. Any rail operator that failed to implement such systems at time of build or upgrade would, in all likelyhood, have their safety case thrown out. Safety case? Italy??? Hello?  |
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Post by Deleted on Oct 23, 2006 14:24:43 GMT
Tripcocks/Trainstops are no longer considered to be, from a risk point of view, 'As Low As Reasonably Practacle' (ALARP). Any new system or any upgrade to an existing system is expected to utilise modern signalling systems. Any rail operator that failed to implement such systems at time of build or upgrade would, in all likelyhood, have their safety case thrown out. Safety case? Italy??? Hello? They are in the EU, and thus do have quite stringent regulations. However, it also one of the more corrupt countries in Western Europe! |
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Post by Deleted on Oct 31, 2006 17:05:08 GMT
Along with.. errr.. Britain! D'oh.
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