SpacePhoenix
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Are PoSA signals (in the UK at least), the ones with two white lights and a red light (to whites for proceed with extreme caution - a white and a red for stop)?
Are PoSA signals (in the UK at least), the ones with two white lights and a red light (to whites for proceed with extreme caution - a white and a red for stop)?
I'm still not clear how it is allowed that a PoSA signal overrides the interlocking (ie. track section ahead is occupied). This seems to be pretty basic safety requirement.... Or am I missing something?
It does seem surprising. But it appears that there are certain procedures that are supposed to be followe before the over-ride signal is used, which the signaller didn't follow. I've not seen it described anywhere what these procedures are. Presumably, they are such that if they're followed, safety is guaranteed.
...To be replaced with a UK-style "have a conversation first, and thus involve two people in the issue" approach. Similarly, the UK style PoSA signal should not be extended to any single or bidirectional line.
The "single line" argument also shows a lack of understanding as the same issue would exist on a single direction track too but you may rear end a unit instead of a head on.
The issue is not quite the same, using the German system at least.
On a single line, a situation can arise that one train is given authority to pass a signal at danger and run on sight, when the other train in the section has passed a green signal and is running at linespeed. Can the PoSA not result in this? It seems the German system could and did. Our system really is pretty safe and should always prevent a collision. I run on a PoSA bi directional line and I'm confident that the system will protect my train.
Two trains in the same section *both* of which had entered on a PoSA or equivalent would, as you say, be much less of an issue as both would be driving on sight.
On a single line, a situation can arise that one train is given authority to pass a signal at danger and run on sight, when the other train in the section has passed a green signal and is running at linespeed. Can the PoSA not result in this? It seems the German system could and did.
Two trains in the same section *both* of which had entered on a PoSA or equivalent would, as you say, be much less of an issue as both would be driving on sight.
Just to be absolutely clear, in UK a PoSA aspect used on a bidirectional line WILL NOT override opposing route locking. If a movement is already signalled in the opposite direction, or an opposing train is still proceeding through the conflicting section after having been signalled by a normal aspect (or indeed a PoSA itself), then an opposing PoSA CANNOT be displayed. The interlocking simply will not allow it. PoSA aspects are designed only to override certain defined equipment failure modes, not to give an unlimited facility for signallers to completely override the interlocking. I do not know what standard interlocking controls apply to a German 'Ersatzsignal' however.
Cheers Marky. Every time you post the technical side of things it makes me warm and fuzzy inside. It serves to reassure me that we do have a safe signalling system and that I can continue to go out there with confidence.
I think I posted up-thread that the Erstaz is not interlocked. (its a local override)
I believe, FWIW, that there were as late as the 1990s German secondary lines with no interlocking whatsoever. Makes you shudder.
As I understand it: procedures. If those are followed to the letter you'll be fine, if not... you can find yourself heading for a head-on collision with another train.I do not know what standard interlocking controls apply to a German 'Ersatzsignal' however.
I believe, FWIW, that there were as late as the 1990s German secondary lines with no interlocking whatsoever. Makes you shudder.
Back in 2011, 10 people lost their lives in the Hordorf (Saxony-Anhalt) crash when a freight train had passed a signal at danger. The line was not fitted with any sort of train protection, at that time PZB was only required on lines with maximum speeds exceeding 100 km/h.
The signaller who was on duty when two trains collided head-on near Bad Aibling in february, has been taken into custody. According to the prosecutor, the man was distracted as he was busy playing a game on his mobile phone. He is being charged with involuntary manslaughter, negligent assault and dangerous interference in rail transport.
Source: Der Spiegel
What a complete fool, if found guilty. However, I still take the view that the system was and is not fit for purpose, in that one allegedly incompetent/inattentive member of staff was all it would ever take to cause a collision.
It is a surprising turn in the investigation of the railway accident at Bad Aibling with eleven dead: The accused Dispatchers had been remanded in custody, said the prosecutor's office in Traunstein. The man was accused of having played on his cell phone shortly before the collision of the two trains an online game and thus to have been distracted.
Investigators see a direct link between the games of the Dispatcher and the cause of the crash: "It must be assumed that because of the close temporal relationship of that the accused was distracted from the control of the crossing traffic of trains." The 39-year-old played accordingly over a longer period on his smartphone.
The Rosenheim District Court had ordered detention for manslaughter, negligent assault and dangerous interference in rail transport. The Traunstein prosecutors pressed upon request give any information about why the dispatcher was remanded in custody.
According to investigators, the man accused by the new findings on his cell phone use not only instantaneous failure, but a significantly heavier weight falling into dereliction of duty. The dispatcher had the trains been wrong signals because of gambling with his cellphone and pressed later for emergency calls to the radio the wrong key combination. He had been playing, but denied to have been distracted.
During the collision of two commuter trains near Bad Aibling eleven people had died on 9 February on the route from Holzkirchen to Rosenheim and 85 passengers were partly critically injured.
The investigation into the causes of the train crash lasted despite the new findings of yet, said the prosecutor. "To date, however, no evidence of interference has shown, could be the cause or a contributing cause of the disaster."
The Ladbroke Grove collision occurred on a newly resignalled layout where the track the departing train was on ended, and points were Set Left so any overrunning train was routed head-on into the Up Main (as happened). They should have been Set Right towards the Down Relief to give Flank Protection fro any overrun, a sideswipe (not that there was any movement signalled alongside) being less of an issue than a head-on, but this somehow wasn't part of the designer's thought.
The signaller who was on duty when two trains collided head-on near Bad Aibling in february has been taken into custody. According to the prosecutor, the man was distracted by playing a game on his mobile phone. He is being held on suspicion of involuntary manslaughter, negligent assault and dangerous interference in rail transport.
Source: Der Spiegel
Germany train crash: Controller 'distracted by computer game'
A German train controller has been arrested over the February rail crash that killed 11 people in Bavaria, as prosecutors suspect he was distracted by a computer game at the time.
According to prosecutors he was playing the computer game on his mobile phone and made a signalling error, then dialled the wrong emergency number.
He has admitted that version of events, German media report.
Two commuter trains collided on a single-track stretch near Bad Aibling.
Eighty-five passengers suffered injuries, some of them life-threatening.
The man could be charged with involuntary manslaughter and could face five years in jail. ....
The signaller who was on duty when two trains collided head-on near Bad Aibling in february has been taken into custody. According to the prosecutor, the man was distracted by playing a game on his mobile phone. He is being held on suspicion of involuntary manslaughter, negligent assault and dangerous interference in rail transport.
Source: Der Spiegel
Although the line has a safety mechanism, prosecutors say the controller mistakenly disabled it, sending two commuter trains towards each other. When he tried to warn the train drivers, he then pressed the wrong alarm button, they say