 Another innovative feature of the steam bogie assembly was the ability to interchange them when faults occurred, an easy operation for maintenance staff when compared to the complexities of overhauling a regular steam locomotive's motion.The three cylinders of each bogie were cast in mono-block format, each surrounded by two annular inlet steam chests and a single large outlet steam chest.These had the added function of keeping the cylinder heated by hot steam to maintain the temperature and pressure of steam entering the cylinders.