The NZR FA class was a class of tank steam locomotives that was built as a larger version of the NZR F class 0-6-0T. The requirements were for larger water and coal capacity on a locomotive that could handle grades better than the F class. Due to costs involved in producing new machines, NZR chose to rebuild existing machines with larger coal and water capacity, larger boiler and firebox, higher boiler pressure and larger diameter pistons.Seven F class engines were rebuilt between 1892 and 1897. Another seven were built new, one at Newmarket Workshops in 1896 and six at Addington Workshops in 1902–03.