NZR Ka class

NZR K^A class

Ka 942 in Kirwee with a excursion to Arthurs Pass in August 2014.

Type and origin Power type Steam Builder NZR Hutt Workshops NZR Hillside Workshops Build date 1939 - 1945, 1950

Specifications Configuration 4-8-4 Gauge 3 ft 6 in (1,067 mm) Wheel diameter 54 in (1.372 m) Wheelbase 34 ft 10 in (10.62 m) Length 69 ft 8 in (21.23 m) Width 8 ft 6 in (2.59 m) Height 11 ft 6 in (3.51 m) Adhesive weight 56.4 long tons (57.3 t; 63.2 short tons) Loco weight 93 long tons (94 t; 104 short tons) Tender weight 52.9 long tons (53.7 t; 59.2 short tons) Total weight 145.9 long tons (148.2 t; 163.4 short tons) Fuel type Coal (original) Oil (converted 1947 - 1953) Fuel capacity 7.5 long tons (7.6 t; 8.4 short tons) coal 1,570 imp gal (7,100 L; 1,890 US gal) oil Water cap 5,000 imp gal (23,000 L) Firebox:  • Firegrate area 47.7 square feet (4.4 m2) Boiler pressure 200 psi (1,379 kPa) Feedwater heater ACFI (KA 930 - 959) Heating surface 1,933 square feet (179.6 m2) Superheater: ​  • Heating area 485 square feet (45.1 m2) Cylinders 2 Cylinder size 20 in × 26 in (508 mm × 660 mm)

Performance figures Power output 1,400 hp (1,000 kW) Tractive effort 30,815 lbf (137.07 kN)

Career Number in class 35 Numbers 930 - 964 Official name "Nigel Bruce" (KA 942) Locale North Island of New Zealand First run 1939 Last run December 1967 Retired 1965 - 1967 Restored 1985 (KA 945) Scrapped 1966 - 1967 Current owner Mainline Steam, Silver Stream Railway, Steam Incorporated Disposition Withdrawn; 3 preserved

The NZR K^A class of 1939 was a class of mixed traffic 4-8-4 steam locomotives that operated on New Zealand's railway network. They were built after the success of the K class to meet the increasing traffic demands of the New Zealand Railways Department. The locomotives first appeared with distinctive streamlining, mainly to hide their ACFI feedwater heater systems.

Following the success of the K class, there was a need for more similar locomotives in the North Island. The new locomotives incorporated a number of improvements, including a re-designed plate frame to eliminate the cracking issues the K class were experiencing; roller bearings on all wheels; hydrostatic lubrication throughout; and the inclusion of the ACFI feedwater heater system as pioneered by K 919. As the ACFI equipment was criticised for its aesthetic appearance, it was obscured with shrouding fitted to both the K^A class and contemporary K^B class.

Building of the locomotives commenced in 1939, just prior to the Second World War. Main construction and assembly took place at Hutt Workshops. Hillside Workshops largely constructed - but did not assemble - ten of the class (No.'s 940-944, 960-964) and built a further five K^A boilers. The primary reason why the ten K^As were not assembled at Hillside was because there was no way of transporting complete locomotives between the North and South Islands at the time (the first Railways Department rail ferry didn't commence until 1962). The Vulcan Foundry, of the United Kingdom supplied parts for fifteen locomotives, including most chassis components, tender bogies, and boiler foundation rings. The General Casting Corporation of Pennsylvania, United States supplied trailing bogie and rear end framing. A company in Auckland also constructed up to 10 tenders for the class. While the imported components were intended for specific locomotives (and in some cases were stamped for the locomotives they were intended for) in practice, and due to wartime pressures, the imported components were used indiscriminately for any K^A locomotives in the programme.