November 23, 2020 | Susan Napier-Sewell

30 Freight Train Wagons Roll Away, ATSB Investigation Highlights Omission of Procedural Step

Thirty freight train wagons rolled away unattended for 1,425 meters from a crossing loop before slowing and coming to a stop just before the end of a siding, road, and level crossing at Bordertown, South Australia.

Around 4:00 pm, November 23, 2019, three locomotive drivers signed on at the Bordertown siding to prepare train 2122S for a journey to Adelaide, South Australia. Train 2122S moved out from the siding and onto the Bordertown crossing loop, where a driver detached the two locomotives so they could conduct a run-around movement and reattached the locomotives to the other end of the train consist.

Train 2122S moved out of siding and onto the crossing loop (green arrow). Locomotives detached for a run-around movement so they could be attached to the other end of the train consist (blue arrows). Source: ARTC, modified and annotated by ATSB (Australian Transport Safety Bureau) for clarity.

The locomotives start the run-around movement by moving out onto the main line (blue arrow). The unattended wagons roll back, pass over the level crossing, bounce over the derailer and continue back into the siding (green arrow). Source: ARTC, modified and annotated by ATSB for clarity.

As the locomotives started the run-around movement, the unattended wagons started to roll back towards the siding. The wagons rolled over a level crossing (which operated automatically as designed), bounced over a derailer (signaling infrastructure on the rail) and continued back into the Bordertown siding.

A driver, still in the siding, observed the unattended rolling freight wagons, so ran alongside and commenced applying the handbrake on one of the wagons. The runaway wagons slowed and came to a stop, having rolled unattended for about 1,425 m. The wagons stopped about 47 m from the end of the siding, a road, and level crossing.

There was only minor damage to the derailer, associated rodding, and slight misalignment of sleepers.

What the ATSB found

The ATSB found that, while detaching the locomotives, the brake pipe air taps were closed by the driver on ground, uncoupling the wagons before a full application of the train air brakes by the driver in the lead locomotive. This prevented further reduction of brake pipe air pressure, so the wagon brakes did not fully apply. In addition, handbrakes were not applied to any wagons. Once the locomotives were detached, the lack of air brakes and handbrakes allowed the wagons to roll away on the descending grade.

While not contributing to the incident, the ATSB also found that the device (a baulk) installed at the siding for restraining runaway wagons was likely insufficient to restrain runaway wagons under some conditions.

Key points:

  • Wagons started to roll back to towards siding as freight train’s locomotives started run-around movement
  • Brake pipe air taps were closed during wagon uncoupling before full application of train air brakes
  • Handbrakes not applied to wagons

What has been done to mitigate or prevent repeat incidents?

Bowmans Rail issued a safety alert requiring uncoupled wagons to have all air exhausted and handbrakes applied when left unattended. The alert also reinforced that all procedures must be adhered to when coupling and uncoupling rollingstock. Additionally, Bowmans Rail has communicated the findings of their investigation and their expectations to train crew, as well as consulted on improvements planned for its Bordertown shunting processes.

The Australian Rail Track Corporation (ARTC) has installed an arrestor bed on the track at the Bordertown dead end, with further works to the arrestor bed planned for late 2020.

What is the safety message came from this investigation? 

This incident highlights how omitting a procedural step may result in over-reliance on remaining protective measures. In this case, the non-application of handbrakes increased reliance on the full application of wagon air brakes to prevent a runaway. However, a slight out-of-sequence implementation of the air brake process resulted in only partial application of the wagon air brakes and the subsequent runaway of unattended wagons. It is essential that all procedural steps are undertaken when uncoupling wagons for run-around movements.

Be sure to read the ATSB report in its entirety to learn further safety measures and more.

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