On 9 February 2016, two Meridian-branded passenger trains collided head-on at Bad Aibling, Germany.

[3] The dispatcher further compounded his error when, upon realizing it, he tried to send emergency codes to the trains but entered the wrong combination into his computer.

[1][4][5] The two trains were Stadler FLIRT3 multiple-units, operated under the Meridian brand by the Bayerische Oberlandbahn (BOB), a subsidiary of Transdev Germany.

[18] The site of the crash was difficult to reach because it lies between the Stuckholz forest and the canalised Mangfall river (Mangfallkanal).

[23] As a result of the crash, the carnival celebrations on Shrove Tuesday in Rosenheim, Bad Aibling and the surrounding area were cancelled.

[27] Police confirmed that nine of the eleven deaths were local men from the districts of Rosenheim and Traunstein, aged 24–59.

[31] In a press conference on 16 February 2016, the local prosecutor (Staatsanwalt) identified "human error" by a train dispatcher at the signalling centre in Bad Aibling as the cause of the crash.

[32] German investigators said they found no evidence of mechanical failure or technical defects that would have caused the crash.

[33] The dispatcher, Michael P., was also charged with gefährlicher Eingriff in den Bahnverkehr (dangerous interference with railroads),[34] which is punishable with up to ten years' imprisonment.

When a Zs 1 subsidiary signal is shown to the train driver, they 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 they are pressing the Written Order button.

After realising he had made an error, allowing both trains to proceed, he dialled an incorrect number when trying to issue an emergency call.

[39] With these new findings the prosecutors reversed their initial assumption of Augenblicksversagen (lapse of attention) turning it into a charge of Pflichtverletzung (breach of obligations), which carries a heavier penalty.

As a result, an arrest warrant was issued, and the train dispatcher was held in pre-trial detention from 12 April 2016.

[43] On the first day of trial, the defendant confessed to the charges 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.

[44][45][46] The expert witness from the EUB investigation board had shown in court that while the documentation for the interlocking section (Betriebsstellbuch) was outdated, slightly incorrect and did not contain directions for the emergency radio, the actual interlocking setup was logical and fully functional in a way that an experienced train dispatcher could handle correctly.

The defendant had not followed general guidelines, including a block signal test (Blockabschnittsprüfung), nor did he radio to the train driver to proceed slowly under the unusual circumstances.

[50] In July 2018 he was released on probation after having served two-thirds of the prison sentence,[51] in accordance with German law (§57 StGB).

The report stated that the infrastructure was fully functional, but that some documentation was slightly outdated (for example, an unused GSM-R radio infill station was listed).

In order to allow track workers to continue to warn a train dispatcher (about an obstacle they have found) Deutsche Bahn did not try to alter the EU-wide harmonized standard but they asked for a second channel at the national regulator (Eisenbahnbundesamt), which was approved.