The WW class demonstrated to be extremely versatile in service, being capable of handling almost any task.

Here, the locomotives worked mostly on coal trains and occasionally hauled branch line passenger services.

During the early 1950s, the decision was made to fit new higher-pitched boilers with deeper fireboxes to four WG class locomotives, Nos.

During the early 1960s, several of the WW class locomotives transferred from the North Island to Greymouth were altered to operate on the Rewanui Incline by the provision of 'trap-door' cowcatchers to clear the centre rail and additional air reservoirs on the tops of the side tanks.

This boiler was purchased for industrial use at the Ford Motor Company plant in the Hutt Valley in the 1970s and was stored at Paekakariki until early 2015 when it was sold to MOTAT to aid the future restoration of WW 491.