The functionality of the Digital Train Radio System (DTRS) did not allow an emergency call to override an initial lower-priority call.
The safety action taken by MTM should reduce risk associated with the safety issue. Improved DTRS functionality that provides automatic override of a lower-priority call would further reduce risk.
Metro Trains Melbourne (MTM) has enhanced its driver training to highlight the operation of the DTRS for normal and emergency use, including the need to cancel a lower-priority call prior to initiating an emergency call. MTM is also reviewing the functionality of similar digital radio systems used by other rail operators, and options for changing the functionality of the DTRS.
The safety action taken by MTM should reduce risk associated with the safety issue. Improved DTRS functionality that provides automatic override of a lower priority call would further reduce risk.
Radio upgrade project
MTM confirmed that there are other systems that enable a higher-priority call to override a lower-priority call. An order has been placed for the functionality of the DTRS to be modified, with new software expected by October 2018. This software will be tested under controlled conditions, trialled on a sub-set of the fleet and subsequently rolled out to the fleet through a controlled program of works.
MTM has modified the digital train radio system software such that emergency and higher priority calls override calls of lower priority. The functionality of the modified software has been confirmed and it is now installed in all metropolitan trains.
ATSB is satisfied with the safety action taken by MTM.
