Too Cold to Stop: The 1971 Aitrang TEE-Derailment
By: Max S
Tags: Disaster, Trains, Germany, Railways, History

The dispatcher, standing less than 500m/1640ft from the site of the derailment apparently doesn’t notice what happened down the track, but due to the wreckage blocking both tracks (and presumably still communicates with the signal-system) his control desk in the signal box shows both tracks as occupied. Knowing that something went very wrong in some way and also knowing that a rail bus was inbound momentarily he immediately withdraws the approach-permission for said bus. It’s unknown if the driver of the rail bus saw the signal change, either way he triggers an emergency stop before running into the wreckage at approximately 40kph/25mph. The lightweight construction of the bus has little to offer against the massive express train’s wreck, 2 people aboard the rail bus are killed and six injured as the bus’ body folds in on impact. All in all 28 people die, 42 survive (19 of which with severe injuries).

The wreckage of the rail bus, folded up against a wheelset from the TEE.

The wreckage during recovery, the motor car can be seen on the right.

Aftermath

Hearing the derailment and subsequent collision in their nearby houses a number of residents are the first people on site, professional responders take another few minutes to reach the scene. One of the locals is the Nieberle-family. The mother and daughter just arrive home around the time of the accident, wondering where the husband and son went. It takes a few minutes for them to realize that the remains of two trains are sitting only a few meters from their backyard, and the two men went to help when the noise of the derailment shook the house. Miss Nieberle, the mother, remembers heading to the neighbors to ask what’s going on, and finding the entire houses’s floor covered in blood. Unwilling to wait for responders, and probably knowing some survivors wouldn’t survive the drive to the hospital, civilians had started rescuing people from the wreckage, taking them to the house and turning the ground floor into a makeshift hospital. When professional responders arrive, some surgeries are performed right on the kitchen table. The Nieberle’s home becomes sort of a media center, housing arriving journalists from the cold weather outside. It seems like half the town is at the site of the accident, so many people want to help that the police has to send people home in order to get the chaos under control. Shortly after the accident the DB sent their recovery-crew, but since the RAm was a Swiss/Dutch train the DB’s experts had little knowledge of it and couldn’t tell responders how to best cut entrances into the mangled cars without risking further harm to the trapped survivors. A local gym was turned into the morgue, with responders trying to match body parts and relatives being asked to help identify victims.

With the rescue and recovery of the passengers concluding during the night investigators took over the site, trying to find out what had caused the prestigious train to turn into a massive field of debris, taking several lives in the process. Neither the TEE’s nor the bus’ driver had survived, so the investigation had to largely rely on physical evidence and the dispatcher’s statement. An early theory that the train driver might’ve forgotten where he was, getting confused in the dark and foggy conditions leading to him going too fast was heavily protested by his coworkers as he had been very experienced, both on the route and in general. Another theory that persists to this day is that the driver had a drug overdose, passed out from alcohol or died from a heart attack before the train even left the tracks. This theory is supported by the train lacking a dead man switch, something that would’ve been mandatory since January 1971. However, an autopsy found no trace of any drugs and alcohol or any sign of a stroke. While investigators could never present a 100% certain cause two main theories exist today:

The Oerlikon brake system installed on the trains had a history of unreliability, valves in the control car would malfunction and keep the full brakes from being applied or released on input from the control car. This had caused several unscheduled stops and even cancelled trains.

A different theory suggested that condensation within the pneumatic lines of the brakes had frozen in the cold night, disabling the brakes in part of the train. This would explain how the brakes on the motor car could be fully applied, emitting sparks, and the train still not decelerating sufficiently. Maybe the valves were fine, the air just couldn’t leave parts of the system so the momentum of the heavy train maintained too much speed for the turn. This was heavily protested by the SBB, the provider of the train, pointing to the train decelerating to 80kph just as it was meant to just a few kilometers away when passing through the town of Kaufbeuren.

The Indusi-system aboard the train ran on a two second delay, it showed no record of the brakes being applied. This contradicted the statement by the dispatcher and the condition of the motor car’s brakes when recovered from the wreckage. In the end the investigation had to list “brake failure” as the cause of the derailment, with no closer specification. It was decided, however, that a warmer temperature might have avoided the collision with the rail bus, as investigators found the icy conditions to significantly lengthen the bus’ braking distance.