Derailment investigation highlights the importance of the consistent application of procedures to control train speed when approaching train order locations

Derailed locomotives NR 54 (lead) and NR 120 (trailing). Source: Pacific National, annotated by ATSB

The derailment of a freight train near Kalgoorlie in Western Australia highlights the need for train crews to consistently apply procedures to reduce train speed in anticipation of a stop indication at train order locations, a new ATSB reports says.

A senior driver and trainee driver were crewing Pacific National train 7MP7 as it travelled from Cook, South Australia, to Parkeston near Kalgoorlie in Western Australia on 19 August 2018 when it approached the points located at the eastern end of the Coonana train order location. Around four hours earlier, the trackside interlocking at Coonana had detected that the point machine at the eastern end had not set correctly for the main line following the passage of a previous train. The colour light indicator (enhancer) situated adjacent to the point machine displayed a red light (stop indication) to the approaching train crew of 7MP7.

During the approach to Coonana, the train crew of 7MP7 maintained track speed while looking for the light displayed by the enhancer ahead. When they realised that they could not see the enhancer, they braked but were unable to stop the train before it traversed the eastern point machine travelling at 44 km/h and derailed. The two lead locomotives, unoccupied crew car and first two platforms of the lead wagon derailed, destroying around 200 metres of the main and crossing loop tracks. The train crew were uninjured.

ATSB Director Transport Safety Dr Stuart Godley said the ATSB’s investigation into the derailment highlights the practice of maintaining momentum approaching a train order location, before confirming the enhancer indication.

The variability in the distance for the effective sighting of enhancers and targets at safety critical locations means the available distance when an indication is sighted may be less than the effective braking distance of the train.

“The variability in the distance for the effective sighting of enhancers and targets at these safety critical locations means the available distance when an indication is sighted may be less than the effective braking distance of the train if the train is still maintaining track speed, which represents a limitation in the system,” Dr Godley said.

“This limitation places the onus on train crews to implement a rule-based procedure to reduce speed at defined locations repeatedly, in preparation for an anomalous event where the enhancer might display a red stop indication.”

The investigation found that a breakdown in verbal communication between the supervising driver and trainee driver controlling the locomotive likely resulted in a misunderstanding of the significance of not sighting the light enhancer, and the urgency of the intended action to brake the train.

“The manipulation of locomotive control inputs in response to the situation highlighted how the on-the-job component of the Pacific National driver competency program did not adequately prepare the trainee driver to control the train in response to an emergency.” Dr Godley said.

Consequently, train 7MP7 approached the eastern end of Coonana at a speed where it was unable to stop before the open points

The investigation also determined that an incorrectly stored lock pin from a point clamp at the Coonana train order location had fouled the indicator’s throw arm pivot mechanism, preventing the correct movement of the points to reset for the main line after the departure of the previous train. 

Since the incident Australian Rail Track Corporation removed all the point clamps and relocated them to the adjacent equipment huts at locations between Malbooma and Parkeson as well as replacing all incandescent type indicators with long-range LED luminaire type indicator units to improve conspicuity of the indication.

Separately, Pacific National have also introduced a signal passed at danger (SPAD) reduction program and reinforced with train crews the need to reduce speed in preparation for stopping short of facing points, until both drivers confirm recognition and understanding of indicator aspects.

Read the investigation report RO-2018-012: Derailment of train 7MP7 at Coonana, Western Australia on 19 August 2018

Last update 10 June 2020

Final report

RO-2018-012: Derailment of train 7MP7 at Coonana, Western Australia on 19 August 2018