They were derived from the F class, replacing the first of the three driving axles with a four-wheel bogie.

It was hoped that the reduced rigid wheelbase would allow the locomotive to provide higher speed passenger services.

The type suffered from lack of weight on the driving axles, a driver stating that "it took the 'G' all its time to push its front bogie along, let alone pull a load".

[3] All of the locomotives were withdrawn between 1915 and 1919 and were sold for further service in industry.

One member from the Castlecliff Branch was subject to a preservation attempt however due to a translation error a Barclay steam locomotive, No.