The South Australian Passenger Transport Authority approved a package of inspection and test plan procedures that did not specify any requirement for tests to verify and validate the safety integrity of the altered level crossing control circuits. The effectiveness of inspection and test plan procedure to control risk and provide assurance the signalling system functioned safety for trains operating on the ARTC network relied solely on the methodology adopted by the subcontracted signal team on the day.
The ATSB is satisfied the Rail Commissioner has addressed this safety issue through the modification of relevant procedures and the program for modification of level crossing controls to reduce the potential for an error when inserting a jumper [bridge].
In December 2020, the Rail Commissioner amended work instruction WI-AM-SP-1234 ‘Signalling System Temporarily Decommissioning and Jumpering’ to include:
2.(2.2) - Adjacent Lines Where temporary jumpering affects adjacent railway (i.e. ARTC), personnel shall ensure the Railway Transport Operator (RTO) have been made aware of the work being undertaken. Where signalling functions on adjacent lines are required to remain active (i.e. level crossing is isolated for AMPRN line but should operate for ARTC movements), the correct operation of those functions shall be verified by the Qualified Employee performing the decommissioning and/or jumpering.
The Torrens Road incident occurred 6 weeks prior to the outsourcing of the operation and management of the Adelaide metropolitan passenger rail network (AMPRN) with Keolis Downer Adelaide (KDA) awarded the contract for the train network that came into effect in late January 2021.
Early discussion with KDA signals engineering focused on reviewing the then practices and to make improvements where necessary. The outcome was the development of EN-OSP-PR-00360 ‘Signal Safeworking Procedure – 02 Temporary Bridging or False Feeding of Signalling Circuits’ and EN-OSP-FO-00361 ‘Authority for Temporary Bridging of Signalling Circuits’ form. The KDA procedure added additional robustness to the process for obtaining a bridging authority, who can carry out the work, planned and unplanned processes, and testing.
On 2 February 2025, the Rail Commissioner insourced the train network, adopting the KDA procedure and form.
In addition to the documentation updates detailed above, physical improvements have reduced error opportunities when temporarily intervening on track circuits. The AMPRN signalling system (specifically on the Gawler Line, Seaford Line, Flinders and first level crossing on Outer Harbor Line) enable crossings to be isolated using remote manual operation, which is applied at the interlocking level removing the need to insert bridging locally.
On the Belair Line, circuit modifications introduced enabled the isolation of level crossings either for the AMPRN or ARTC individually, or both, by a simple application of bridging at accessible terminals rather than at the back off relays, removing the potential error of inserting the bridge in the incorrect relay contact. Further work on the remainder of Outer Harbor locations was to be captured as part of ongoing signalling system upgrades.
