NZR A class (1873)

New Zealand A class (1873)
A67 at Ocean Beach Railway
Type and origin Power type Steam Builder Dübs & Co. (12), Yorkshire Engine Company (2) Build date 1873 (12), 1875 (2)
Specifications Configuration: ​  • Whyte 0-4-0T Gauge 3 ft 6 in (1,067 mm) Driver dia. 30 in (762 mm) Wheelbase 5 ft 7 in (1.70 m) Length 18 ft 0 in (5.49 m) Loco weight 11 long tons (11.2 t; 12.3 short tons) Fuel type Coal Fuel capacity 0.4 long tons (0.41 t) Water cap 330 imperial gallons (1,500 l; 400 US gal) Firebox:  • Firegrate area 4.2 sq ft (0.39 m2) Boiler pressure 120 psi (827 kPa) Heating surface 269 sq ft (25.0 m2) Cylinders Two, outside Cylinder size 8 in × 15 in (203 mm × 381 mm)
Performance figures Tractive effort 3,072 lbf (13.7 kN)
Career Operators Public Works Department, NZGR Number in class 14 Locale New Zealand Preserved Four (62, 64, 66, 67) Disposition Four preserved, ten scrapped

The NZR of A class of 1873 consisted of three types of similar specification but differing detail. The first and most numerous from Dubs and Yorkshire Engine Co., the next from the Wellington firm E.W. Mills Lion Foundry, and the last from the Scottish firm of Shanks. The specifications are for the Dubs/ Yorkshire engines.

The A class was the second class of steam locomotive (after 1872's F class) ordered to work on New Zealand's national railways. Initially ordered by the Public Works Department for use in the construction of lines in Cantebury and Taranaki, the A class was a small tank locomotive with a wheel arrangement of 0-4-0T. An initial twelve were constructed by Dübs & Co. in 1873 and two more were built in 1875 by Yorkshire Engine Company. They were not just used by the Public Works Department; the New Zealand Government Railways also utilised the class to operate revenue services on smaller branch lines. Quickly outmoded for use on the lines they helped build, only one (A62) remained in government service by 1905, used on the NZR's Stores Branch tram line at Piha. Their small size made them perfect for use on bush tramways and small private industrial sidings. Many members of the class survived for decades in private use, and although all are now retired from commercial service, four have survived to be preserved by railway enthusiasts and two of the four are currently in full operational condition. One of these preserved locomotives, A 67, was the first in a cavalcade of locomotives at the celebration of the hundredth birthday of the Dunedin Railway Station.

A batch of A class engines, with differing external details was built at Wellington's Lion Foundry, by E.W. Mills Ltd in 1873, for use on the Foxton Section. These appear to be the first NZR locomotives actually built in the country. Like other so-called contractors engines they were quickly outmoded for line haulage and were sold to industrial operators. "Opossum" was sold in 1877 and served industrial and timber companies for eight decades. The other two were likewise sold by 1885.