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German Train Crash


phil-b259

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According to news reports there has been a head on collision on a single line at/near Bad Aibling; the number of fatalities and casualties is - not surprisingly - subject to updating.  All the Wiki article would seem to have done is repeat those quite widely reported facts without any sort of comment regarding cause (which would obviously be pure speculation).  For once whoever wrote the Wiki article appears to have kept his words very much on the straight and narrow.

 

I don't have much time for Wiki except sometimes as a guide where to look for better quality information but at least this one seems to be as accurate as the news reports (various).

 

A terrible event and I condolences to all those affected by it.

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Yes I have. But a wiki page is by design not a reliable source of info, let alone "known facts" in a rapidly changing situation as an accident (in this case involving trains). It was made shortly after the crash, when it wasn't (yet) apparent that it claimed 9 lives so far, so the "known facts" reputation is shot straight away. :rolleyes:  Don't get me wrong, the wiki page has its place, after publication of the investigation reports :yes:

The figure of 9 fatalities was edited into the page at 11:43 when the revised number was known, there was no second guessing as soon as the page was created 

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Sorry does it really matter about the rights and wrongs of Wikipedia

 

Many people have lost there lives and many more injured, that a were our thoughts should be at this tragic time.

 

Get a grip on reality.

 

Terry

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What is PZB90? I understand some single track lines in Germany still used a timetable based system on single line which has resulted in casualties in the past.

 

My condolences to the families of all involved, especially the drivers and train crew.

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I'd imagine the fact modern multiple units were involved rather than older stock means the loss of life and injuries were minimized though with the closing speeds involved

it's all relative. I was looking at the new Meridian units at Munich Hbf back in October and thinking to myself how the modern stuff was rather soulless and sterile but in a situation like this modern design is a blessing. 

 

My thoughts and sympathies to all those affected.

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What is PZB90? I understand some single track lines in Germany still used a timetable based system on single line which has resulted in casualties in the past.

 

My condolences to the families of all involved, especially the drivers and train crew.

PZB90 is the latest version of the German standard  Indusi train control system developed since the 30s. It has trackside inductors (outside the rails rather between them) which are energised at different frequencies to pass speed controls to passing trains, similar in idea to AWS and TPWS. From what I can gather there aren't many (any?) passenger lines without it now.

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What is PZB90? I understand some single track lines in Germany still used a timetable based system on single line which has resulted in casualties in the past.

PZB90 is the latest version of the German standard  Indusi train control system developed since the 30s. It has trackside inductors (outside the rails rather between them) which are energised at different frequencies to pass speed controls to passing trains, similar in idea to AWS and TPWS. From what I can gather there aren't many (any?) passenger lines without it now.

PZB basicly transmits the signal aspect in a reduced form to the driving loco. The most important here is the 2000 Hz influence which is transmitted when passing a red signal and causes the train to stop immediately. As there cannot have been green signals for both trains the big question is why the second train has not been stopped if both signallers have behaved correctly (which at present is not at all clear). PZB by now is in use on every state owned line, this was different at the time of the Hordorf Accident in 2011, but a retrofitting programme was started immediately afterwards. Newest press releases report that the working order of the PZB equipment on the line was checked just 1 week ago and there have not been any faults.

 

Personally I am more interested in how the second train got on the line. As mentioned there could not have been green signals for both trains. One or both signaller (Fahrdienstleiter) must have waved through a train or two on a fallback level. Let's wait and see.

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PZB90 is the latest version of the German standard  Indusi train control system developed since the 30s. It has trackside inductors (outside the rails rather between them) which are energised at different frequencies to pass speed controls to passing trains, similar in idea to AWS and TPWS. From what I can gather there aren't many (any?) passenger lines without it now.

I understood that there are still some gaps on local and low speed lines but all single lines were to be fitted by 2014.

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Some rather distressing coverage on the BBC 13.00 news the two Flirt Trains were certainly flattened into each other, plus the difficulties of the emergency crews getting to the passengers because of the proximity of the line to the river and also being on a curve so that neither driver had a lengthy sight of the approaching train.Aircraft type "black boxes "were on board both commuter trains

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Found myself getting seriously annoyed with the coverage and the ensuing debate on the Jeremy Vine show on Radio 2 today.

 

In particular Jeremy Vine himself. Utter buffoon.

 

Rob.

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Found myself getting seriously annoyed with the coverage and the ensuing debate on the Jeremy Vine show on Radio 2 today.

 

In particular Jeremy Vine himself. Utter buffoon.

 

Rob.

Pretty much my late wife's view in 2007 when he interviewed her (by phone to our remote cottage here) about the then current French healthcare issues affecting incomers. In fact he made such a mess of it that a rerun had to be done some weeks later when his researchers had done a better job. When the news is fresh and emerging he's on his own.....

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Could not. I saw this question coming.

 

All Stellwerke on single track lines do work to the principle of Erlaubniswechsel. Only one of the two stations of a single line can have the Erlaubnis which translate as allowance/permitment to send trains to the other. Giving of the Erlaubnis first locks all Exit Signals on the transmitting station, then unlocks the Exit Signals of the other station. This was done from the earliest days of Signalling.

 

LM_1993-05-29_085_1-023_Dia01_300x100000

Second field from the right is an Erlaubnis field. It is currently unblocked, hence white, so the Fahrdienstleiter can send trains. When the other end of the single line wants to send a train, after a telephone call the Erlaubnis field is operated and becomes red here, while at the same time it becomes white on the other end. Then the signals here are locked and cannot be pulled off.

 

Those fields by the way are no rocket signs, the comprise of little more than a spring, vertical rockets, a crank with an inductor (mains electricity was not available everywhere in the 1900s) and a white/red disc which can move upwards or downwards.

 

ea.jpg

Push button type of the above. This would be on the left hand end of a track mimic diagram and shows the direction of Erlaubnis with arrows. In this photo the Signaller does not have the Erlaubnis and therefore cannot clear signals. In relay interlockings like here the arrows double as block indicators: When it turns red, the opposite station has blocked forward which is comparable to UK's "Train on Line" (though Germany follows the open block principle, hence no "Line blocked", hence only two block positions (clear and occupied, or white and red)).

 

The operation of Erlaubnis is always the same, from mechanical to Computer signalboxes: You cannot "grab" the Erlaubnis, the other one has to give it to you. Erlaubnis indicators always have a handle/button/context menu to transmit the Erlaubnis.

 

EDIT: Further Reading on Block Working and Erlaubniswechsel here: http://www.joernpachl.de/German_principles.htm#manual%20block

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Getting back on topic, the two stations guarding the single track line where the accident has happened are controlled by SpDrS 60 type interlockings. Usually one of them is remotely controlled by the other one, but I cannot comment on if that was the case today morning. If so, both trains were under the Fahrdienstleiter supervision of the same human.

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