Topic summary
Axle box

Extracted from the Wikipedia article List of railroad truck parts.
Axlebox
Plain bearings are now illegal for interchange service in North America. As early as 1908 axle boxes contained a set of long cylindrical rollers allowing the axle to rotate. It was also used on steam locomotives such as the Victorian Railways A2 class, the LMS Garratt, the LSWR 415 class, and the GCR Class 1.