Wednesday, February 11, 2026

Safety Alert RSA-2026-001: Steerable bogies

ONRSR has identified a potential issue with steerable bogies, whereby the steering mechanism on the bogie degrades and causes elevated wheelset dynamics and excessive piston travel on bogie-mounted brakes, resulting in loss of braking effort.

The steering mechanism on steerable bogies is designed to control wheelset dynamics and maintain bogie wheelbase while allowing the wheelsets to orient radially in curves. Typical steering mechanism components are shown schematically below and include:

a) Two sub-frame adapters connected to bogie side frames (not shown) by adapter rubber pads, and

b) Two cross anchors connected to the sub-frame adapters by pins and bushes.

If the steering components on steerable bogies are not designed and maintained to required standards, and become degraded:

a) Wheelsets can undergo elevated dynamic movements causing increased wheel-rail forces and derailment risk on poor track; and

b) Bogie wheelbase can vary dynamically, which can negatively affect bogie-mounted brake performance.

Rolling Stock Operators (RSOs) must ensure:

a) Rolling stock inspections identify signs of wear, degradation and ineffective function of steerable bogie components such as adapter rubber pads and cross-anchor bushes.

b) Steering mechanisms on steerable bogies are functioning correctly to control wheelset dynamic movement and maintain wheelbase.

c) Bogie-mounted brakes function correctly when bogies and/or brake rigging are in the worst allowable condition.

RSOs should examine all risks associated with wheelset dynamics and braking performance on their rolling stock, including in minimum maintainable condition.

RSOs procuring, or considering procuring, steerable bogies with components such as adaptor rubber pads and cross anchor bushes should ensure these components meet required standards and should be aware of the extra maintenance associated with steering mechanisms.

This advice is effective immediately.