Extending the lifetime of journal bearings for high-speed trains

The research described in this paper addresses a particular rolling stock component for high-speed-rail applications: the journal (or axlebox) bearing, which is the one of the topics of the GEARBODIES research project. The paper summarises the first three phases of the project: 1. terms of reference, requirements and specifications, 2. assessment and selection of technology concepts, 3. development through investigations and lab testing. After the final validation phase, the work-plan will lead to the proposal of low Life-Cycle Cost (LCC) bearing Design Concepts for the high-speed trains of the future, with a focus on extra- and ultra-long bearing lifetime. In the paper, the identified lifetime targets and the selection of the technology concepts are described. Some key technologies investigated in the project are then discussed. Firstly, High Entropy Alloys (HEA), for the bearing components in rolling contact, show huge potential due to the unprecedently vast possibility of fine-tuning their properties by varying their composition. Secondly, polymer/lubricant combinations are being investigated, with a focus on the ageing properties of polymer bearing cages for ultra-long lifetime. Thirdly, lubrication solutions, with a focus on oil lubrication as a promising technology concept to obtain the long-lasting extremely low frictional dissipation required for long lifetime.