Technology naturally changes over time and the evolution of wheelset and bogie design has had a significant impact on the bearings used in train applications. Early train designs used simple bushings and plain bearings, but as wheelset and bogie designs became more complex and sophisticated, roller and ball bearings were developed to handle increasingly high loads, speeds, and a range of environmental conditions. Some train designs rely on bearings such as tapered roller bearings and cylindrical roller bearings, which are designed to provide improved ride quality and reduced wear on the wheels and bearings – but are for many not considered the most effective solutions. Overall, the development of wheelset and bogie design has made bearing selection more challenging, but also led to the development of more reliable and advanced bearing solutions for modern train applications.

One of the main limitations of plain bearings is their relatively high friction, which can result in increased wear and heat generation, as well as reduced efficiency. Roller bearings, on the other hand, are designed to reduce friction and improve load capacity, making them a more efficient and reliable option for train wheelsets. Roller bearings use cylindrical or tapered rollers that are arranged in a cage, which reduces friction and allows the bearing to handle higher loads and speeds with less wear and heat generation.

The transition from plain to roller bearings marked a significant milestone in rail engineering. However, one of rail’s biggest bearing revolutions was the move from “open” bearings to sealed, pre-lubricated bearings units, such as tapered bearing units and cylindrical roller bearing units.