The ATSB is reminding rail operators of the risks surrounding unsecured loads.
An ATSB investigation into the April 2012 derailment of a ballast train near Broken Hill, NSW shows how uneven loading of wagons can lead to instability, with the potential for serious incidents or accidents.
The train comprised two locomotives hauling 34 ballast wagons and one ballast plough car at the rear for the purpose of distributing ballast along a re-sleepered track. Ballast is the coarse stone used to form the bed of the railway track. The ballast wagons were AHBY class ballast hopper type with discharge doors in the middle of the wagon.
The day before the incident, a front end loader loaded ballast into the wagons from a ramp constructed from ballast adjacent to the track. The filling procedure was to place a bucket load at each end of the wagon with crew visually checking every bucket load to ensure there was no discharge under the wagon. The train was then stabled for the night. When preparing the train for departure the next morning the crew noticed that the middle door on one of the wagons was open and a small amount of ballast had discharged from it. Because the discharge seemed small, they assumed the wagon was still full and that the load would have remained stable.
Shortly after the train's departure, the crew noticed 'dust and sparks' coming from the rear of the train. After stopping and inspecting the train, the crew discovered that the 26th wagon had derailed both bogies (wheeled undercarriages). Four kilometres of track was also considerably damaged.
The ATSB investigation showed that the discharge door of the wagon had been left open and had discharged a large amount of material during shunting operations before the train set off. As a result, the load had become seriously uneven. The wagon then derailed on a curve. Similar incidents have been reported of trains carrying coal and other bulky cargoes.
To ensure wagons are evenly loaded, rail operators should ensure they follow and carry out their load distribution checking procedures to the required standard.Last update 04 January 2013