Due to a shortage of suburban engines in the Sydney area and the availability of surplus C79 class tender engines, it was decided to experimentally convert one of the tender locomotives to a tank type engine in 1896. The conversion proved successful and twenty had been converted at Eveleigh Railway Workshops by 1902. In 1924 the class was renumbered becoming the Z13 class.
Following the delivery of C30 class locomotives from 1903, they were transferred to Newcastle suburban traffic and when replaced there, were allocated minor roles such as working the Carlingford, Morpeth and Warren branches. Two were sold to East Greta Mining & Railway Company, one to Ashtonfields Colliery, Thornton and a fourth scrapped.