NZR S class

The NZR S class was a class of seven 0-6-4T single Fairlie steam locomotives used in New Zealand.

The locomotives were ordered by the New Zealand Railways Department (NZR) in 1880, and delivered from the Avonside engine works in 1881–1882. They were considerably larger than the earlier R class, and all saw service in the Wanganui district, with its abundance of sharp curves and grades. These two classes of Single Fairlies were considerably more popular with the engine crews than their older Double Fairlie counterparts, which often suffered frame breakages whilst operating in the Wanganui district.

In the 1880s despite complaining of a lack of motive power, the residing chief mechanical engineer T.F. Rotheram arranged the shipment of three of this class to the Western Australian Government Railways in 1891, where they were classified as the I class.