What exactly does the valve gear do and what types are there?
There are numerous valve gears, most of which are named after their designer, Walschaerts, Baker, Hackworth and Stephenson are some common types.Some are outside valve gears and have all their working linkages clearly visible, as with Walschaerts and some are inside and are hidden from view between the frames of the engine. Whatever the type of valve gear or size of loco, they essentially do the same job of controlling the flow of steam to and from the cylinders at the correct time. This is known as the ‘valve events’. They also allow the engine to run in either direction by shifting the valve events by 180 degrees. Most current ROUNDHOUSE ‘Classic Series’ loco’s are fitted with a simplified Walschaerts valve gear and changing from forward to reverse can be accomplished manually by moving a reversing lever in the cab or by radio control from a distance. Hackworth valve gear is found on the ‘Charles Pooter’ and ‘Carrie’ models which are also reversed by means of a lever in the cab. Loco
