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Destroyed S-Bahn in Munich: collision in the curve
Photo: Matthias Balk / dpa
The S-Bahn Munich warned of "objects on the road" of the S7 in its first message on Twitter on Monday.
In hindsight, this is somewhat strange news, because there are very large objects that are still blocking the S-Bahn line in the south of Munich: Two S-Bahn trains, wedged together and partially pushed off the track.
Torn-out pieces of metal show the exact place where they met.
Some of the doors of the two tracks are hanging crookedly in the brackets or have jumped open, ladders laid in the embankment by the helpers lead up there.
A bright light in the crashed front car testifies to police and expert investigations underway there.
On the ground of the parallel federal highway 11, used blue disposable gloves are a reminder of the big rescue operation on Monday evening, in the background a generator chugs, which the Federal Agency for Technical Relief installed for the work.
On Monday afternoon at around 4.40 p.m., two S-Bahn trains crashed head-on into each other on the S7 route in the south of Munich.
A passenger, a 24-year-old Afghan from the Wolfratshausen district, who was behind the driver's cab of the train heading into town, was killed in the crash and 18 people were injured, six of them seriously.
The scene of the accident is in a curve north of the Ebenhausen-Schäftlarn station, the line is single track there.
The train driver is said to have canceled the braking initiated by the system
Investigators have now leaked the first insights into how the accident could have happened.
The results are preliminary, the investigations by the public prosecutor's office, state police, federal police and Federal Railway Authority are still ongoing, the police and public prosecutor's office only want to provide information on Thursday.
But one scenario seems plausible, following a pattern of similar accidents on single-track lines.
According to this, the driver of the train, which left the double-track S-Bahn station heading north and downtown, may have run over a signal.
He drove into the section of the route that he thought was free, but on which the S-Bahn was traveling from the opposite direction with a delay of several minutes.
The train driver is said to have canceled an emergency braking initiated by the safety system.
It is still unclear whether this was actually the case and why the train driver might have acted in this way, whether and what kind of communication there was with the dispatcher, and also whether there were frequent indications on the route that then turned out to be wrong, all of this is still unclear.
In any case, the approaching S-Bahn then approached the oncoming train in a left turn, which is said to have also received a red signal and was slowed down.
Its driver is said to have informed the dispatcher about it.
The braking distance was no longer sufficient
This, in turn, is said to have warned the driver of the train leaving the S-Bahn station of the impending collision.
He probably braked, but it was probably not enough to avoid the collision.
Whether the investigators' assumption is correct should be clarified, among other things, by evaluating the tachographs, which were recovered from the destroyed railcars.
The two train drivers are among the seriously injured and were not yet able to be questioned on Tuesday.
According to the Bavarian Interior Minister Joachim Herrmann (CSU), the investigations are currently focused on human error.
The focus is currently "that one of the train drivers could have made a mistake," Herrmann said on Bavarian radio.
A final clarification is still pending.
Transport Minister Kerstin Schreyer (CSU) also said it was probably not a technical failure.
As on other single-track routes, several safety levels have been installed on the Munich route of the S7 to prevent trains running in opposite directions from colliding.
A train may only leave the two-track stations if it is certain that the section of track in front of it is free.
Only then does the engine driver get a green signal from the signallers in the respective signal boxes.
"The rules are similar to a construction site traffic light," explains a spokesman for Deutsche Bahn when asked.
"A single-track section may only be traveled in one direction at a time." In addition, almost all routes - including the affected Munich S-Bahn - are equipped with a safety system called "punctual train control" (PZB 90).
This triggers emergency braking if a red signal has been passed.
human vulnerability
However, such systems have a weak point that has repeatedly come into play in accidents: the human factor.
The systems only work if those responsible, whether on the railways or in the signal box, do not overrule them because they misjudged the situation.
The Munich accident is based on a well-known discussion: whether single-track railways can be adequately secured at all.
Leaving all safety systems aside, one simple fact of transport planning remains: one track and two trains, in the event of a conflict, that is one track too few or one train too many.
Disastrous accidents have occurred more frequently on single-track lines.
Six years ago, twelve people died in Bad Aibling, also in Upper Bavaria, when two trains collided head-on on a single-track line.
At the time, the fault lay with the dispatcher, who, distracted by a mobile game, had set the wrong signals.
He was convicted of involuntary manslaughter, among other things.
Last summer, a passenger train from Munich en route to Prague in the Czech Republic collided with an oncoming train, also on a single-track line, killing three people.
Shortly thereafter, there was a near-accident in the district of Garmisch-Partenkirchen.
Not only remote or poorly developed branch lines are single track, but a third of the highly frequented Munich S-Bahn network, especially further out of the city.
Only six months ago, two S-Bahn trains approaching each other were able to brake just in time on the S7 accident route, just four kilometers from Schäftlarn.
A train driver was then suspended after he had interpreted a signal as a departure command.
In fact, it was an order to drive slowly.