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A decline in rail lubricator maintenance leads to derailment on a small-radius curve

The ATSB is highlighting the importance of effective rail lubricator maintenance to reduce the risk of derailment on small-radius curves.

Metro Trains Melbourne passenger train derailed near Rushall Station in Melbourne, Victoria

The ATSB’s investigation into the derailment of a Metro Trains Melbourne (MTM) passenger train near Rushall Station in Melbourne on 6 February 2016 has been released.

At about 1650, the passenger train was negotiating the most severe mainline curve on the metro network when the lead bogie of the second car derailed.

The investigation, carried out by the Victorian Office of the Chief Investigator, Transport Safety, on behalf of the ATSB under the Transport Safety Investigation Act 2003, found there had been a decline in the standard of maintenance of the network’s rail lubricators.

Victorian Chief Investigator, Transport Safety, Chris McKeown said that in the months leading up to the derailment, rail lubricator maintenance was being transferred from an outside provider to MTM staff and this transition was not adequately managed, resulting in a deficiency in lubrication throughout the network.

In small-radius curves, effective rail lubrication is critical to reduce friction and the risk of flange-climb derailments.

“In this instance, the low levels of lubrication on the small-radius Rushall curve lead to excessive friction between the train’s wheel flanges and rail gauge-face on the curve and this caused the front right-hand wheel of the second car to climb the outside rail of the curve.”

“The link between the amount of friction and lubricant film thickness is well-established. The higher the film thickness, the lower the level of friction between the wheel-flange and rail.

“In small-radius curves, effective lubrication is critical to reduce friction and thus the risk of flange-climb derailments.”

To reduce the risk of future derailments on similar curves, MTM have taken a number of steps to improve rail lubrication across the network, including installation of new electronic lubricators and the updating of its track fault management system with specific guidance on wheel-climb risks.

Read the full investigation report RO-2016-002: Derailment of MTM train TD1064 near Rushall Station, Melbourne, Victoria, on 6 February 2016

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Last update 16 May 2018