Right hand side injector with delivery pipe (black) and overflow pipe installed
Left Hand side coupling rods installed awaiting Cross Head and connection rod to be fitted
Right Hand side coupling rods installed, connecting big end brass on middle crank pin to establish fit of Top hat washer that retains rods on the middle crank pin. The front crank pin shows special coupling rod retaining washer with recessed drive, the forerunner of a Hexagon socket drive. This is required on the leading crank pins due to restricted clearance behind the crosshead, yet to be installed
Valve gear connecting link on Left Hand side between the rocking arm (on left) the transmits the valve gear motion from inside the frame to outside the frames to the valve spindle (on right). The special castellated nuts (also called castle nuts) allow a split pin to lock the nut once tightened . These GWR special nuts have 4 slots unlike the normal propriety castle nuts that have 3 slots. Thus the GWR nut can have 8 positions per revolution rather than 6 for the standard nut. Split pins yet to be fitted.