Bad Aibling rail accident

Accident

The accident occurred just after 06:47 CET (05:47 UTC) on the single-track Mangfall Valley Railway (German: Mangfalltalbahn) on a curve between the stations of Kolbermoor and Bad Aibling-Kurpark close to the Bad Aibling sewage works in Bavaria. As of 11 February 2016, a total of 11 people had died, including several railway employees. In total 85 people were injured; 24 injured seriously and 61 injured less seriously.

The two trains were Stadler FLIRT3 multiple-units, operated under the Meridian brand by the Bayerische Oberlandbahn (BOB), a subsidiary of Transdev Germany. The eastbound train was a six-car unit with 333 seats (ET 325), scheduled to run from Munich to Rosenheim, while the westbound train was a three-car unit with 158 seats (ET 355), scheduled to run from Rosenheim to Holzkirchen. There were more than 150 passengers on board the two trains, considerably fewer than usual because of Carnival Holidays. The trains were equipped with a total of three train event recorders. The line and both trains were equipped with the Punktförmige Zugbeeinflussung (PZB) train protection system, which was designed to reinforce line-side signalling and prevent drivers from accidentally passing signals at danger.

The eastbound and westbound trains were scheduled to pass each other at Kolbermoor railway station, with the westbound train (M 79506) towards the direction of Munich timetabled to wait for five minutes for the eastbound train from Munich (M 79505) to arrive. The westbound train departed Kolbermoor on schedule but the eastbound train was four minutes behind schedule. Each train was travelling at about 100 kilometres per hour (60 mph) at the time.

Rescue operation

The rescue operation involved a total of approximately 700 emergency service workers, including 180 firefighters, 215 Bavarian State Police officers, 50 Federal Police officers, 30 federal civil protection employees of Technisches Hilfswerk, and 200 rescuers from the Bavarian Red Cross, including Water Rescue and Mountain Rescue units. A total of 11 helicopters took part in the rescue efforts. Air ambulances from both Germany and Austria were used to transport the injured to hospitals.

The site of the accident was difficult to reach because it lies between the Stuckenholz forest and the canalised Mangfall river (Mangfallkanal). This made rescue work considerably more difficult, meaning rescue workers had to be transported by boat and casualty extraction supported by air ambulance. Injured people were extracted by boat across the canalised Mangfall river to the opposite bank.

Recovery operation

On 9 February 2016, two breakdown cranes belonging to the DB Netze Emergency Technical department (DB Netz Notfalltechnik) were dispatched from Fulda and Leipzig to assist in recovery and removal of the two damaged trains. The crane from Fulda is capable of lifting 160 tonnes, and the second crane from Leipzig is capable of lifting 75 tonnes.

Reaction

German Transport Minister Alexander Dobrindt visited the site of the accident. He said it was a "horrifying sight". Bavarian Interior Minister Joachim Herrmann said that it was "difficult to comprehend" how the accident happened. Chancellor Angela Merkel said she was "dismayed and saddened" by the crash. German Foreign Minister Frank-Walter Steinmeier stated: "My deepest sympathy goes to their families." Minister-President of Bavaria Horst Seehofer said "The whole of Bavaria has been shaken".

As a result of the accident, the carnival celebrations on Shrove Tuesday in Rosenheim, Bad Aibling and the surrounding area were cancelled. The traditional political debates on Ash Wednesday in Lower Bavaria were called off.

Investigations

The German Rail Accident Investigation Agency (Eisenbahn-Unfalluntersuchungsstelle des Bundes, EUB) opened investigation number 04/2016 into the accident. The German police opened a separate investigation. Police confirmed that nine of the eleven deaths had been identified as being local men from the districts of Rosenheim and Traunstein aged 24–59. The cause of this accident was unclear. By the evening of 9 February 2016, Federal Transport Minister Alexander Dobrindt reported that two of the trains' three train event recorders had been recovered. The third was still located in one of the wedged train carriages. On 12 February it was announced that the third event recorder had been recovered. Police said that the recorder was damaged, but attempts would be made to extract the data. Data from the other two recorders had thus far provided no indication of human error on the part of the train crew.

In a press conference on 16 February 2016, the local prosecutor (Staatsanwalt) identified "human error" as the cause of the crash. A train dispatcher at the signalling centre in Bad Aibling (identified in the trial as "Martin P") had given a wrong instruction. German investigators said they found no evidence of mechanical failure or technical defects that would have caused the crash. The dispatcher was also charged with gefährlicher Eingriff in den Bahnverkehr (dangerous interference with railroads), which is punishable with up to ten years' imprisonment.

Many German railway main signals are equipped with an additional subsidiary signal called "Zs 1" (shown as three white dots in a triangle shape). This subsidiary signal replaces a written order with the authorization to pass the signal while showing a stop aspect. The train dispatcher can activate it from the signal box. There are no safety controls in the signal box, other than operating rules, to activate a Zs 1 signal. There are special procedures needed for operations to ensure train safety, before a signaller is allowed to turn on the subsidiary signal Zs 1. When a subsidiary signal Zs1 is shown to the train driver, he must press and hold the PZB button "Befehl" ("Order") in the cab while moving the train over an active 2000-Hz emergency stop inductor located at the main signal. A warning tone sounds in the cab to acknowledge to the driver that he is pressing the Written Order button. After passing the stop signal (at a speed not exceeding 40 km/h (25 mph)) and any following points with the complete train, the train may continue with normal speed, unless the main signal also has a distant signal at the same location. The subsidiary signal Zs1 is supposed to be used only in circumstances when a route for a train cannot be set. There are sections in the rulebook on how and when it may be activated safely, but according to the local prosecutor, these rules were not adhered to. The exact timing of actions and signals, as recorded on the train event recorders and at the signal box, as well as the radio protocols, are under investigation (as of 18 February 2016).

In April 2016 it was revealed that the dispatcher had been playing a game on his mobile phone at the time. After realizing he had made an error, allowing both trains to proceed, he dialled an incorrect number when trying to issue an emergency call. No technical fault existed with either the trains or the signalling system. With these new findings the prosecutors reversed their initial assumption of "Augenblicksversagen" (lapse of attention) turning it into a clear "Pflichtverletzung" (breach of obligations) which faces heavier penalty — as a result an arrest warrant was issued, and the train dispatcher was held in pre-trial detention since 12 April 2016. The prosecutors brought the charges to the court Traunstein in mid July 2016 with accusations on twelve accounts of "fahrlässige Tötung" (involuntary manslaughter, i.e. murder by negligence) and 89 accounts of "fahrlässige Körperverletzung" (involuntary battery, i.e. injury from negligence). The main trial was scheduled for seven days between 10 November and 5 December 2016. On the first day of trial the defendant confessed to the offences brought by the prosecutors, but his lawyer wanted the degree of guilt to be evaluated during the subsequent proceedings - although he showed a degree of compassion for the victims, the defendant refused to answer questions on the intensity of his preoccupation with the mobile game. He was subsequently jailed for 3½ years.

The expert witness from the EUB investigation board had shown in court that the documentation for the interlocking section (Betriebsstellbuch) was outdated, slightly incorrect and it did not contain directions for the emergency radio. Nethertheless the actual interlocking setup was logical and fully functional in a way that an experienced train dispatcher could handle correctly. The defendant, however, had not followed general guidelines for problem handling - if he had double-checked the existing routes (Blockabschnittsprüfung) on the signal box panel, then he should have easily spotted the route set for the train from Kolbermoor that was automatically blocking the exit signal for Bad Abling. Neither did he radio to the train driver to proceed slowly under the unusual circumstances. The original error had occurred somewhat earlier however - with one of the trains running late he chose to move the train crossing from Kolbermoor to Bad Aibling, by juggling some of the signals. With a delay of only four minutes, however, this action was not allowed. The court ruled on 5 December that he was guilty on all of the charges - Martin P was sentenced to three and a half years in prison.