Project number: COF-G25

Reduced maintenance costs thanks to suspension component

Prototype enhanced trailing arm bush shows potential to reduce a vehicle’s primary yaw stiffness, leading to a reduction in wheel-rail surface damage.

‘The reduction in primary yaw stiffness represents a great potential in reducing track and wheel damage.’

Dr Joseba Murua
(Dynamics & Rolling, Innovation Lead) and Mr Manuel Fossati (Head of Bogie Engineering, Technical Direction), CAF Rail UK Limited

The challenge

The damage caused by wheel-rail contact forces during curving makes up a significant amount of the overall cost of maintenance.

One way of reducing the wheel and rail wear is to reduce the vehicle’s primary yaw stiffness (PYS).

However, by increasing the lateral acceleration of the vehicle, it also worsens the passengers’ ride experience. In extreme cases the vehicle instability can lead to a derailment.

What we did

We brought together a range of stakeholders including Network Rail, train manufactures, bushing manufacturers and ROSCOs.

Together, we finalised the design of an enhance trailing arm bush (ETAB), built a prototype, and perform component testing, and modelled expected benefits.

Benefits delivered

The research showed that the optimised design of the ETAB is capable of a step change in reduction of PYS.

As a result, we can significantly reduce damage at the wheel-rail interface. This can significantly lower track and wheelset maintenance costs. If we calculate benefits based on the difference for a Mark 4 fleet and consider improvements over the existing brush, this work could save £19.3m per fleet over 20 years.