The K class was the first Garratt locomotive class, built for Tasmania in 1909.
Tasmanian Government Railways ordered two K class locomotives, K1 and K2, for the North East Dundas Tramway in western Tasmania. Built in 1909, they were compact 0-4-0+0-4-0 tank locomotives designed for difficult narrow-gauge industrial and mining terrain.
The Garratt arrangement placed the boiler, cab and fuel supply on a central frame carried by two independently swiveling engine units. This gave the locomotive more flexibility on sharp curves while allowing a large boiler and firebox for its size. The Tasmanian K class worked over steep grades, tight curves and rugged trestle bridges.
These pioneers were unusual compared with later Garratts. They used compound cylinders, with high-pressure cylinders on the rear engine unit feeding larger low-pressure cylinders on the front unit. Their cylinders also faced inward. K1 survives today, while K2 was scrapped, making the class especially important in Garratt history.