Wagons with mismatched wheel sets were occasionally to be found. Wheels and bearings were standardised by the Railway Clearing House but provided that the axle journals and bearings were correct for the wagon capacity then it was OK.
Wheels of the standard dimension (37.5 inch diameter on the tread) were made with plain spokes, split spokes and a variety of disc centres. There were two common axle journal sizes for plain oil lubricated bearings - 4.25" x 9" for wagons up to 16 ton capacity, and 5" x 10" for wagons over 16 tons. Axle boxes which contained the bearing and supported the springs also came in a variety of designs but the commonest were either divided, or open fronted.
It was very unusual to find a wagon with roller bearings on one axle and oil bearings on the other however I discovered two 27 ton mineral tippers in Tinsley yard with Isothermos bearings on one axle and open fronted axleboxes on the other.
