NZR WAB class

NZR WAB class
WAB 794 on its first excursion after restoration, with the Capital Connection rolling stock, on 31 August 2003.
Type and origin Power type Steam Builder NZR Addington Workshops, Christchurch (1+1) NZR Hillside Workshops, Dunedin (12+8) A & G Price Limited, Thames (3+5) Build date 1939
Specifications Configuration: ​  • Whyte 4-6-4T Gauge 3 ft 6 in (1,067 mm) Wheel diameter 54 in (1.372 m)[1] Wheelbase 33 ft 1 in (10.08 m) Length 44 ft 6 in (13.56 m)[1] Adhesive weight 41.85 long tons (42.52 t; 46.87 short tons)[1] Loco weight 74 long tons (75 t; 83 short tons)[1] Fuel type Coal Fuel capacity 3.0 long tons (3.0 t; 3.4 short tons)[1] Water cap. 1,700 imp gal (7,700 L; 2,000 US gal)[1] Firebox: ​  • Grate area 33.0 sq ft (3.07 m2)[1] Boiler pressure 200 psi (1,379 kPa)[1] Heating surface 1,050 sq ft (98 m2)[1] Superheater: ​  • Heating area 183 sq ft (17.0 m2)[1] Cylinders Two[1] Cylinder size 17 in × 26 in (432 mm × 660 mm)[1]
Performance figures Maximum speed 60 mph (97 km/h) Power output 1,000 bhp (750 kW)[1] Tractive effort 22,250 lbf (99.0 kN)[1]
Career Number in class 30 (16 WAB+14 WS) Numbers 687 - 798 Locale All of New Zealand First run 1918 - 1926 Retired 1967 - 1972 Scrapped 1969 - 1972 Current owner Feilding and District Steam Rail Society (1) Disposition Scrapped, three preserved

The NZR W^AB class locomotives were steam locomotives designed, built and used by New Zealand Railways Department (NZR). Their wheel arrangement is described by the Whyte notation 4-6-4T. The locomotives were designed by NZR chief draughtsman S.H. Jenkinson as tank versions of the A^B class 4-6-2 Pacific locomotive. Initially, the locomotives were separated into two classes, designated W^AB for mainline work and W^S for suburban work.^[2]

The remaining locomotives were kept in service until the last days of steam, operating short-haul mainline freight services and fast suburban services, particularly in Auckland. W^AB 794 was sold to the Ohai Railway Board in Southland for running heavy coal trains. The locomotives were progressively withdrawn in the 1960s.^[2]