Similar to crankshaft bearings in a car, these locomotive bearings are made of brass with a thin layer of white-metal cast onto the internal cylindrical face.
The process is fraught with difficulties and opportunities for the process to fall; the white-metal must be heated to just the right temperature and not “over cooked”, impurities need to be remove before casting, bearing faces must be clean and have adequate grooves to lock the white-metal in place, and the layer must be just the right thickness. Failure to achieve these things will result in the white-metal fracturing and peeling away from the brass backing, causing considerable damage.
Following some investigation into solutions other railways had developed, and based on our experience with modern hard wearing plastics, the engineering team developed a design for a brass side rod bearing with a bearing shell machines from a hard wearing grade of Nylon.
