SBB accident: Sust pleads for new door locking system
Today, the Swiss Safety Investigation Authority (Sust) published an interim report on the fatal SBB accident in Baden. Sust has identified two malfunctions in connection with the anti-trap system.
Source: Sust interim report
As already known, the train manager Bruno R. (54) was trapped and dragged along on August 4, 2019 at Baden station during the door closing process (see report here). According to the Sust interim report, the anti-trap protection of door 4 in the fifth last car of type EW IV did not work.
The Sust interim report states: "Two malfunctions were detected in the anti-trap system. The loose connection (see photo) at the pressure wave switch of door 4 meant that the closing force of the door was not reduced when it encountered an obstacle. The anti-trap protection was therefore not effective. The 'Door closed 98%' sensor is intended to deactivate the anti-trap function shortly before the door is finally closed. Since this sensor does not always respond at the same position, the anti-trap function cannot ensure its intended function. Therefore, it cannot be ruled out that the anti-trap function is not deactivated shortly before the final closing of the door, but earlier."
Sust safety recommendation
In its interim report, Sust recommends replacing the current system for inactivating the anti-trap protection of unit car IV with a reliable system.
The investigating body also speaks of a safety deficit: "Persons or objects trapped in the doors must be detected with a high degree of certainty. The current EW IV system with the parallel connection of two door limit switches does not meet this requirement. The door can be reported to the locomotive driver as closed even though it is not completely closed. This leads to uncertainty among locomotive crews and can cause accidents." For this reason, Sust advocates having the EW IV door limit switch system adapted so that the red indicator lamp shows the locomotive driver that the doors are in the correct state.
According to Sust, the present results are not conclusive and will require further in-depth investigations.
Union: fault does not lie with the accident victim
What does the Transport Workers' Union (SEV) say about the Sust interim report? According to the SEV, this report clearly showed that technical defects were the cause of the tragic accident of the train manager, i.e. that the fault did not lie with the accident victim.
The union is calling on SBB to withdraw from service wagons of the EW IV type on which the anti-trap system does not work. In a second step, as described in the Sust interim report, the current system for inactivating the anti-trap protection should be replaced by a reliable one. In addition, SBB would have to deploy additional qualified personnel in maintenance.
The detailed interim report of the safety investigation authority can be here can be read.
