Rail safety issues and actions

Axle fatigue susceptibility

Issue number: RO-2017-013-SI-02
Who it affects: All users of 840P1 axles
Issue owner: Incitec Pivot Limited
Operation affected: Rail: Rolling stock
Background: Investigation Report RO-2017-013
Date: 12 June 2019

Safety issue description

The GATX 840P1 axle was susceptible to fatigue cracking due to relatively minor damage that was not reliably detected prior to failure.

Proactive Action

Action organisation: Incitec Pivot Limited
Action number: RO-2017-013-NSA-005
Date: 12 June 2019
Action status: Monitor

Following the derailment of train 9T92, Incitec Pivot Limited (IPL) performed in-situ MPIs on the entire GATX wagon fleet. By the end of September 2018, it had detected 17 cracked axles and removed them from service. The company has also increased the frequency of axle non‑destructive inspection and is also introducing an improved axle design for its GATX fleet.

IPL contracted a provider to conduct a crack growth rate study on the 840P1 axles. The study revised previous work with findings based on kilometres travelled. As a result of that study, IPL has increased the inspection frequency to an inspection target of 50,000 km travelled (with an allowable maximum of 65,000 km). The inspection frequency will continue over an expected four year period (or sooner, based on attrition) until the 840P1 axles are replaced with the improved version.

Predicted point of failure graph

Predicted point of failure graph. Source: Incitec Pivot Limited

Source: Incitec Pivot Limited

The Office of the National Rail Safety Regulator will also work closely with IPL to address the susceptibility of the GATX 840P1 axle to fatigue cracking due to relatively minor damage.

ATSB response:

The ATSB notes that the action initiated by IPL, once implemented, should address the safety issue.

Current issue status: Safety action pending
Status justification:

The ATSB notes the response provided and that the action initiated by Incitec Pivot, once implemented, should address the safety issue.

Last update 13 June 2019