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Project number: 2021-STN-018

A new guidance note about the aerodynamic rolling moment coefficient improves safety


Guidance Note GMGN2542 has been developed. It replaces Code of Practice GMRC2542 issue one: Recommendations for Determination of Aerodynamic Rolling Moment Coefficient.
'It is a good complement for the method in the Resistance of Railway Vehicles to Roll-Over in Gales document.'
Mikel Iraeta
Aerodynamics Engineer, CAF

The challenge

It has been over 15 years since the previous code of practice was published.

In that time:

  • A British Standard covering wind tunnel testing has been developed.
  • Research has been carried out.
  • Numerical approaches have been shown to be as good as wind tunnel testing.

This project aimed to improve the guidance for the determination of aerodynamic rolling moment coefficients for railway vehicles. This is important for the evaluation of vehicle safety. It is also needed to reduce the risk of fatalities or injuries to passengers and staff.

What we did

The document has been revised and republished in a modern format as a guidance note.

It includes the option to use computational fluid dynamics for calculating vehicle aerodynamic coefficients. Also, it adds relevant guidance from RSSB research project T1028.

The provision of content in a modern format should also better assist users.

The work involved a railway aerodynamics technical specialist. They were supported by a project manager and administrative functions.

Benefits delivered

Preventing vehicle overturning is vital to keep the risk of fatalities or injuries low.

The project delivered several benefits by updating the guidance on determining aerodynamic rolling moment coefficients.

  • Including the option to use numerical methods reduces costs in some cases.
  • The guidance is aligned with recent RSSB research and British Standard BS EN14067-6. This, and the fact that we have addressed user enquiries, will improve the understanding and application of the document.

The guidance also contains a previous amendment. The hope is that this aids user visibility.