A faulty on-board information system has been blamed for the collision of a Pacific National train and an Aurizon train on Queensland’s Mount Isa Line at Oonoomurra in February.
The last wagon of Pacific National containerised freight train 9211 derailed when it was struck by the lead locomotive of Aurizon fertiliser freight train 9T66 just before midnight on February 27, 2018.
Nobody was injured in the incident.
The Aurizon train had been heading west to Phosphate Hill, having started its journey in Townsville. The Pacific National train was on its way east to Townsville, having left Mount Isa.
The trains had to pass at a section of single track at Oonoomurra. This required the Aurizon train to enter a crossing loop.
With the Aurizon train out of the way, the Pacific National train passed through the section of track, and stopped when the driver believed it was no longer obstructing the track ahead of the Aurizon train.
The Network Control Officer at Townsville subsequently directed the Aurizon train to continue.
“The crew of [Aurizon] train 9T66 entered Oonoomurra travelling at about 25 km/h,” according to an incident report released by the Australian Transport Safety Bureau on November 21.
“As the train rounded a sweeping left curve at the western end, the crew sighted three empty container wagons at the rear of train 9221, with the last wagon fouling the track. The driver made an emergency brake application but was unable to avoid a collision.”
The collision caused minor damage to the lead locomotive of the Aurizon train and, and the last wagon of the Pacific National train, derailing its trailing bogie.
The ATSB said the collision had occurred because the driver of the Pacific National train believed the vehicle to be clear of the track, when in fact it was not.
“The driver stopped the train when the [on-board] length counter [showed the train had] travelled 1,069 metres,” the Bureau’s report states. “Considering the train length (rounded to 1,000 metres), the driver calculated that the rear wagon should be in clear of the adjacent track by around 70 metres.”
The Bureau found the on-board information system in the Pacific National train’s lead locomotive was operating in a “degraded state,” and was therefore showing erroneous speed and distance information to the driver.
Additionally, the ATSB said, “the Pacific National procedures to determine and communicate the serviceability of a locomotive to operate as a lead were inadequate,” and “the rail traffic crew relied solely on the displayed indication of distance travelled to determine the train was in clear and did not validate the distance travelled against the length of their rail traffic and the distance available in the loop…”
As a result of the incident, Pacific National says it has verified the accuracy of systems on each 83-class locomotive in its fleet, and the process for advising rail traffic crew to use alternative methods to validate accuracy of displayed information.
The operator has also introduced procedures for maintainers to identify restrictions to locomotives operating as lead.
“In the longer term, PN undertook to investigate procedural or locomotive-based system changes to alert rail traffic crew of an inconsistent speed fault,” the ATSB said.
“Rail traffic crews on both trains undertaking a cross at a directional travel station under the Direct Traffic Control safeworking system must validate rail traffic is complete and in clear prior to releasing the block to the rear of the rail traffic and prior to entering a block following receipt of a proceed authority,” the Bureau concluded.