Enrico Betterle
Mermec

Equivalent conicity

According to last issue of related regulation (EN 15302:2021) one of our Italian customer, which is currently monitoring the entire High Speed passenger fleet by means of automatic wheel profile measuring system, started looking in a more analytical way at the wheelset Equivalent conicity evolution over time.

The EQ is an exceptional indicator of the behaviour of the bogie (and hence the train) and the way it interacts with the rail, based on actual wear of the wheel and the rail: this information is crucial both for safety and for maintenance purposes.

We supported our customer in this analysis and, together with him, we developed new rules to feed the Maintenance Management System in order to predict critical hunting behaviour, which would lead to train alert and consequent speed limitation.

In our presentation we would go through this use case, sharing data and details on the rule, and positive outcomes and further future applications and developments.

Wheel Out Of Roundness

The topic is focused on a novel approach to detection of wheel polygonization (out of roundness) not based on indirect force measurement (WIM/WILD systems) but inspecting and monitoring over time, on a statiscal basis, the wheel diameter, as measured directly on the wheel running tread. This work comes from a specific use case we investigated from a Far-East customer, operating a metro line, therefore it is based on real data. In our presentation we would go through this use case, sharing data and details on the new approach, explaining the benefits in terms of maintenance and planning.

Vehicle & Track Affinity Index

Based on our deep experience in the wheelset EQ (see above), train weighing and rail measuring/monitoring, we are developing a new combined indicator for Vehicle to track affinity, based on the calculation of the Nadal Limits. We are therefore combining information from:

• Wheelset gauge, EQ, and wheel profile.
• Axle weight and unbalance.
• Track gauge and rail profile.

This to compute an affinity index expressing the criticality of one unknown vehicle respect to a known railway infrastructure network where the vehicle is routed. This would allow to understand excessive stress to the track caused by unstable or worn/deteriorated vehicles or to prevent more dramatic consequences.

In our presentation we would discuss the research project, the technology behind the scenes and the railway stakeholders involved. We would discuss the positive outcomes both from safety and maintenance perspectives.