Bearing refurbishment for Alstom

28 April, 2016

The yoke type track roller, which was custom designed by Schaeffler in the early 1990s specifically for use on the Pendolino train, is part of a yoke type track roller unit that is used on the coach body tilting system. In conjunction with the rails, the yoke type track roller units act as a roller-supported cradle system, which allows the coach body to tilt into bends in the track in such a way that the direction of the coach body axis matches the resulting acceleration.

Operationally critical

The yoke type track roller unit complete or ‘Tilt Roller Bearing’ comprises two bearing assemblies, a bespoke split core resilient bushes and a two-part tilt roller housing. The built-up assembly is bolted to the bogie frame – two per bogie – these provide the base dynamic stability for the profiled and hardened ‘tilting shapes’ to travel over when the train is operating in tilting mode. Without the robust and reliable tilt roller yoke bearings, the key tilting capability of the class 390 Pendolino would not be able to operate. The yoke bearings are very reliable units and have performed consistently between overhauls.

Gary Timmings is supply chain manager for special projects and overhauls at Alstom in Wolverhampton and is responsible for managing material availability for the 60-week overhaul programme at Alstom’s Repair Depot in Longsight, Manchester. He comments: “The tilting mechanism on a Pendolino train is a critical system as the train relies on this to enable it to operate at optimum speeds (up to 125mph) along the West Coast Mainline. It is essential that these systems operate reliably at all times because if they don’t, this will have a detrimental effect on the overall operational performance of the train and on the efficiency of the West Coast Mainline. Alstom therefore operates a heavy overhaul maintenance regime on the tilting systems.”

In March 2015, Alstom began overhauling the entire fleet of 56 Pendolino trains at Longsight. A critical part of this overhaul is the refurbishment of the yoke type track rollers by Schaeffler. The 60-week programme involves the overhaul of a trainset worth of bogies per week (22 for an 11 car set and 18 for a nine car set). Each bogie is fitted with four yoke type track rollers per bogie, which means that every week Alstom engineers need to remove 88 or 72 yoke type track roller units and send these to Schaeffler for refurbishment. The units are replaced with newly refurbished units from Schaeffler’s Refurbishment Centre in Schweinfurt, Germany.