The reference for locomotives and railcars
New Zealand Railways classes WAB and WS
New Zealand | 1917 | 30 produced
W<sup>AB</sup> 786 in July 1926 at Hillside
WAB 786 in July 1926 at Hillside
Albert Percy Godber / Godber Collection, Alexander Turnbull Library

In 1917, two tank locomotives were built in the Addington workshops with boilers that were originally intended for class AB Pacifics. These now had an additional trailing axle and many common parts with the Pacific, which simplified maintenance. Two almost identical variants were built in series, which were designated as WAB for use on main lines and as WS for use in suburban traffic. Between 1947 and 1957, some WAB were replaced by other locomotives, after which eleven were rebuilt into class AB tender locomotives. In the sixties the remaining WAB were retired.

ManufacturerAddington, Hillside, A & G Price
Axle config4-6-4T (Hudson) 
Gauge3 ft 6 in (Cape gauge)
Dimensions and Weights
Length44 ft 6 in
Wheelbase33 ft 1 in
Fixed wheelbase10 ft
Service weight160,160 lbs
Adhesive weight94,080 lbs
Axle load31,360 lbs
Water capacity2,042 us gal
Fuel capacity6,720 lbs (coal)
Power sourcesteam
Indicated power1,000 hp (746 kW)
Optimal speed27 mph
Top speed60 mph
Starting effort23,655 lbf
Power Plant
Driver diameter54 in
Boiler pressure200 psi
Expansion typesimple
Cylinderstwo, 17 x 26 in
Grate area33 sq ft
Firebox area123 sq ft
Tube heating area1,022 sq ft
Evaporative heating area1,145 sq ft
Superheater area277 sq ft
Total heating area1,422 sq ft
Calculated Values
steam locomotive
last changed: 11/2023

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