NZR JA class

NZR JA class
JA 1271 with excursion consist on approach to Ahuriri on 14 February 2003.
Type and origin Power type Steam Builder NZR Hillside Workshops (35) North British Locomotive Company (16) Build date 1946–1956
Specifications Configuration: ​  • Whyte 4-8-2 Gauge 3 ft 6 in (1,067 mm) Wheel diameter 54 in (1.372 m) Wheelbase 34 ft 10 in (10.62 m) Length 66 ft 11.5 in (20.41 m) Adhesive weight 44.45 long tons (45.16 t; 49.78 short tons) Loco weight 69.1 long tons (70.2 t; 77.4 short tons) Tender weight 40.35 long tons (41.00 t; 45.19 short tons) Total weight 109.45 long tons (111.21 t; 122.58 short tons) Fuel type Coal (Hillside) Oil (North British) Fuel capacity 6.0 long tons (6.1 t; 6.7 short tons) coal 1,350 imp gal (6,100 L; 1,620 US gal) oil Water cap. 4,000 imp gal (18,000 L; 4,800 US gal) Firebox: ​  • Grate area 39.0 square feet (3.6 m2) Boiler pressure 200 psi (1,400 kPa) Feedwater heater None: Fitted with Davies & Metcalfe Exhaust Injector Heating surface 1,469 square feet (136.5 m2) Superheater: ​  • Heating area 283 square feet (26.3 m2) Cylinders Two Cylinder size 18 in × 26 in (457 mm × 660 mm) Valve gear Baker
Performance figures Maximum speed 75 miles per hour (121 km/h) Tractive effort 24,960 lbf (111.0 kN)
Career Number in class 51 Numbers 1240 – 1274 (Hillside) 1275 – 1290 (North British) Locale All of New Zealand First run 1947 – 1956 (Hillside) 1952 (North British) Last run 16 November 1971 Retired 1967–1971 Scrapped 1969–1972 Disposition Seven preserved, remainder scrapped

The NZR J^A class was a class of fifty-one 4-8-2 steam locomotives operated by the New Zealand Railways Department (NZR). The locomotives were built in two batches; the first batch was constructed at the Hillside Workshops at Dunedin between 1946 and 1956, while the second batch was constructed by the North British Locomotive Company (NBL) of Glasgow, Scotland in 1951. To differentiate between the two batches, the locomotives were identified by their builder.^[1]

The J^A class was the last steam locomotive class to be produced by the NZR, with the Hillside-built J^A 1274 being the final steam locomotive ever built. The North British J^A class were also the last steam locomotives imported for the NZR.

The J^A class had relatively short service lives of between 12 and 24 years as they were replaced by diesel locomotives as part of the dieselisation process of the NZR. Nine J^A class managed to last until the end of steam on 26 October 1971.