What happened
On 10 July 2013, a pre-planned and advertised Local Possession Authority (LPA) was implemented on the Up Main line between Revesby and Turrella.
Approximately 30 minutes after the LPA was implemented, passenger train 709C entered the limits of the possession area and immediately ran over railway track signals (detonators) and was brought to a stand. There were no injuries or damage.
What the ATSB found
The ATSB’s investigation found that an LPA was an appropriate method of authorising the work to be performed. However, a combination of individual actions and systemic issues contributed to the incident. Two Special Train Notices (STNs) were published, one highlighting the limits of the LPA (called the proforma) and the other advising of altered train running (or pathing) arrangements. When implementing the LPA, two Sydney Trains area controllers working the Revesby control panel incorrectly assumed the limits of the LPA were at the city end of Revesby (clear of 51 points) rather than the country end (clear of 55 points). As a result blocking facilities were applied at the wrong location. These actions were partly influenced by a deficiency in the train pathing STN, which routed city-bound trains via 51 points. A final amendment to the proforma STN, extending the possession limit to 55 points, was not accounted for in the pathing STN, resulting in the two STNs being incompatible and contrary to engineering and pathing requirements when implemented.
A number of Sydney Trains’ procedures were examined to determine if any area of the planning, advertising and implementation of the LPA contributed to the incident. The ATSB found that the key parties involved in the implementation of the LPA did not come to a mutual understanding of the possession limits and other potential entry points or impact to train running arrangements. Documented procedures were not accurately followed and critical safety information was not confirmed by train control. The ATSB also found that there was an over-reliance on informal and verbal handover procedures amongst area controllers.
What's been done as a result
As a result of the incident, Sydney Trains implemented changes to STN production and validation processes. Sydney Trains also updated the signal box phone list and the Protection Officers Handbook which were published on their RailSafe website. Sydney Trains proposes to undertake targeted assurance in relation to adherence to safety critical communications protocols in LPAs in order to determine whether the non-compliances revealed in this investigation represent a systemic failure.
Safety message
In order to minimise errors prior to implementing LPAs, key parties should come to a mutual understanding of the possession limits and impact on train running, and ensure that altered train running (pathing) is compatible with the advertised possession limits. Rail operators should also recognise that handovers leading up to or during the implementation of an LPA increase exposure to the possibility of error and that this risk can be mitigated if train controllers, signallers and protection officers comply with documented procedures, protect all entry points and repeat back safety critical information.