 The design also featured raised running plates above the wheels, which allowed easy access to the inside of the frames for purposes of lubrication. The lack of wheel splashers on this running plate also reduced the risk of the bearings overheating, by allowing more air to flow around the axles when at speed. Wheel splashers were used on older locomotive designs to box-in the top portion of the driving wheels for aesthetic reasons, and to prevent water and dirt from being thrown at the cab windows. The "Britannnias'" footplate was designed around the requirements of the operating crews, with a mock-up being constructed at Crewe to test ergonomics and usability. For ease of maintenance, availability of spare parts and increased reliability, two sets of Walschaerts valve gear were used, along with the largest cylinders capable of staying within the British loading gauge. The "inside" cylinders located between the frames of a three- or four-cylindered locomotive are difficult to access for maintenance; the two-cylinder design of the Class 7 – with all the valve gear on the outside – avoided these maintenance problems. Boiler' plumbing ' was also generally exposed to maintain ease of access. In common with other BR standard designs there was no exhaust injector, as this device was temperamental unless rigorously maintained.
