NZR FA class

New Zealand Fa class
Type and origin Power type Steam Builder New Zealand Government Railways Total produced 20
Specifications Configuration: ​  • Whyte 0-6-0ST Gauge 42 Driver dia. 36 in (0.914 m) Wheelbase 10 ft 6 in (3.20 m) Length 26 ft 6 in (8.08 m) Loco weight 19.2 long tons (19.5 t) Fuel capacity 1.6 long tons (1.6 t) Water cap. 450 imp gal (2,000 L; 540 US gal) Firebox: ​  • Grate area 10.7 sq ft (0.99 m2) Boiler pressure 160 psi (1.10 MPa) Cylinders Two, outside Cylinder size 12 in × 18 in (0.30 m × 0.46 m)
Performance figures Tractive effort 9,090 lbf (40.43 kN)

The New Zealand F^a class was built as a larger version of the tried and true 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 preasure and larger diameter pistons. Thirteen F class engines were rebuilt between 1892 and 1897. F^a276 was built new at Newmarket Railway Workshops in 1896.

Improvements

Due to longer distances being travelled, it became clear that the standard F class were unable to cope due to their limited coal and water capacity. The first twelve locomotives rebuilt to class F^A between 1892 and 1895 were designed to overcome this problem. The locomotives were re-equipped with Walschaerts valve motion, new side tanks and cabs, and a larger boiler. Nominally, the extent of the changes meant that very little of these locomotives actually remained from the original.

Although they were now more powerful than the F class and were reasonably successful, the F^A class was hampered like the L^A 4-4-0T rebuilds in that their coal bunkers were too small. The decision was made in 1897 to extend the frames of F 9, then undergoing conversion at Addington Workshops, and fit an extended coal bunker. To accomodate this, a two-wheeled trailing truck would be added.

Initially, F^A 9 was classified as an F^B class locomotive to differentiate it from the 0-6-0T conversions. Once its success had been confirmed, all of the F^A class locomotives were rebuilt to the F^B class specifications between 1900 and 1905. Following the completion of the final conversion in 1905, all locomotives were reclassified as the F^A class once more.

Plans had existed in 1901 to rebuild further F class locomotives, but these were scrapped and in 1902-03 a further six F^B class locomotives, numbers 315 and 372-376. These locomotives differed from the other rebuilds in having a redesigned frame and piston valves in place of the original slide valves fitted to the earlier rebuilds. F^A 9 also differed from the standard rebuilds in that its trailing truck had outside journal boxes instead of the internal type used on the other engines.

Withdrawal

The F^A class saw little work after 1919 due to increases in traffic and in part to their complexity over the standard F class. The locomotives were progressively withdrawn up until 1943, when the last locomotive of this type, F^A 250 (based at Westport) was sold to the Whakatane Board Mills for use on their Matahina Tramway in the Bay of Plenty. Most were scrapped and their boilers fitted to F class locomotives.

During their working lives, the F^A class locomotives were reboilered at least once, with the original boilers being fitted to members of the F, G, and L class locomotives among others. As a result, most preserved F and L class locomotives have a F or F^A class boiler in place of the original type of boiler. While this provides a degree of standardisation, it is somewhat negated by the fact that these boilers come from different makers and have differences in internal fittings such as the dry-pipe.

Industrial Use

Like the NZR F class, members of the F^a class also saw service after being retired from NZR service. A couple were put to use on forestry lines, and a couple were converted to Diesel propulsion by meat processor AFFCo Ltd.

Class register

Road Number	Workshops	Date Converted to Fa 0-6-0T	Workshops	Date Converted to Fb 0-6-2T	Withdrawn	Notes
9			Addington	1897	1943	Industrial use 1943-c.1990 Dieselised 1953. Preserved Bay of Islands Railway.
10	Addington	1893	Hillside	1903	1919	Industrial use 1919-1940.
41	Addington	1893	Hillside	1903	1937	Industrial use 1937-1980. Preserved Bush Tramway Club.
157	Addington	1895	Hillside	1903	1923	Industrial use 1923-1927.
179	Petone	1894	Petone	1904	1930
182	Petone	1893	Petone	1904	1928
186	Petone	1895	Petone	1903	1929
226	Petone	1892	Petone	1903	1930
242	Newmarket	1892	Newmarket	1904	1930
244	Newmarket	1895	Newmarket	1905	1930
247	Newmarket	1892	Newmarket	1904	1929
250	Addington	1892	Westport	1900	1943	Industrial use 1943-1966. Preserved Glenbrook Vintage Railway.
251	Addington	1892	Hillside	1903	1939	Industrial use 1939-1954.
Engines	Built	New
276	Newmarket	1896	Newmarket	1904	1931	Built new. Only NZR locomotive built in Auckland.
315			Addington	1902	1936	Built new.
372			Addington	1902	1936	Built new.
373			Addington	1902	1936	Built new.
374			Addington	1903	1936	Built new.
375			Addington	1903	1936	Built new.
376			Addington	1903	1931	Built new.