The maximum flange width compatible with our infrastructure
There is currently no limit on the worn maximum flange width set out in the requirements for the control of geometry for railway wheelsets in Railway Group Standard GMRT2466 – Railway Wheelsets (GMRT2466). Changes in the design of modern passenger vehicles meant that this needed to be reviewed.
Modern passenger vehicles have been designed to achieve good curving performance and stable running. As the vehicles run on track with good track quality, the wheelsets deviate less from the centre line of the track and consequently, there can be higher tread wear focused on the tread centre of each wheel profile.
This effectively increases the flange which could create incompatibility with existing infrastructure and create potential risk, so this issue needed to be reviewed.
Through the Strategic Partnership with the University of Huddersfield, potential hazards were investigated, with the aim of making recommendations on maximum flange limits in GMRT2466.
This included curving analysis, the effect of increased flange width on equivalent conicity, the effect of flange thickness on rolling contact fatigue, interaction with switch blades, and interaction with switches and crossings.
The study concluded that the check rail can become ineffective where there is interference between rails and wheelsets with larger flange thickness, and there is potential for increased wear of wheels and damage to crossing noses. The study therefore recommended a maximum flange width.
Although this research recommended maximum flange widths, in the majority of cases these limits will not need to be actively managed. Where active management is required, this research provides evidence that will allow the industry to proactively manage the emerging risk.
These changes will be incorporated into the next revision of Railway Group Standard GMRT2466, and management of thick flanges will be incorporated into standard maintenance procedures.