New Zealand Government Railways 2-6-4 Locomotives in New_Zealand

Class Details by Steve Llanso of Sweat House Media

Class Wd (Locobase 4961)

Data from [] accessed in January 2002. Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 23, p. 125.

Deliveries came in May 1901-February 1902; the engines were numbered in order of their production numbers, as shown below:

316-327 (18543-18554)

355-360 (19259-19264)

The longer wheelbase of the 2-6-4 arrangement must have appealed to the New Zealand operators. And indeed consensus emphasizes the design's versatility as it worked "all kinds of trains." Each engine operated for more than three decades, the first retirement coming in January 1933, the last in March 1936. Several of these were used to buttress riverbanks and some have been recovered.

Four went on to serve industrial owners. Two had very short second careers. Wilton Colllieries, Ltd bought Wd 356 in January 1933 and 316 in April 1934, planning to use them on the company's 9.5 km (5.9 mile) private railway just north of Hamilton, North Island, between Ngauruwahia and Glen Massey, but less than a year later both were declared unserviceable and sold for scrap.

Ohai Railway bought Wd 317 in December 1934 to run between Ohai and Wainio (about 8 miles apart in Southland between Caroline Peak and Invercargill), which it did for almost a decade before it was stored in 1944 and then scrapped.

Wd 357 apparently benefited from four years of storage before it was sold to the Timaru Harbour Board in 1938; Timaru lies on the east coast of the South Island between Christchurch to the north and Dunedin to the south. Thousands of tons of rock from the quarry traveled along the tramway to the harbor to expand it and to export. After 26 more years of work in Timaru's quarry, the 357 was donated to the New Zealand Railway and Locomotive Society's Canterbury Branch.

Class Wf (Locobase 5190)

Data from John Garner's comprehensive site at [] ... (October 2002). See also Wikipedia's entry on the Wf at [], accessed 12/12/12.

Built for suburban service by three different suppliers, all New Zealand. The NZGR shops at Hillside produced 16, the Addington shops 10, and AG Price of Thames 15.

Like their contemporary Wds, these engines were quite satisfactory and served for a long time, most into the 1950s, several into the mid-1960s.

In 1939, however, the Tasmanian Government Railways inquired if any locomotives of the Ww class were available to relieve a power shortage. The Wws were not, but four Wfs-- 381, 385, 436 and 437--were overhauled and rebuilt to meet TGR specifications and delivered as the DS class. The next four--392, 405, 431 and 434--were refitted with welded boilers first, then delivered.

Although welcome, the locomotives "were not particularly successful," says Wikipedia, "as the TGR used soft coal, which the WF class boilers were not capable of burning economically." Reliability issues led to modifying the DS 7 "by shortening the smokebox by 520mm and fitting a narrower funnel." Although successful, the DS 7's makeover was not extended to the rest of the class.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID4961 5190
RailroadNew Zealand Government RailwaysNew Zealand Government Railways
CountryNew ZealandNew Zealand
Number in Class1841
Road Numbers316-327, 355-360
Number Built1841
BuilderBurnham, Williams & Coseveral
Valve GearStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)10 / 3.0510 / 3.05
Engine Wheelbase (ft / m)17.59 / 5.3627 / 8.23
Ratio of driving wheelbase to overall engine wheelbase 0.57 0.37
Overall Wheelbase (engine & tender) (ft / m)27.59 / 8.4127 / 8.23
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)65,408 / 29,66960,256 / 27,332
Engine Weight (lbs / kg)97,888 / 44,40197,888 / 44,401
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)97,888 / 44,40197,888 / 44,401
Tender Water Capacity (gals / ML)1020 / 3.861140 / 4.32
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)3 / 2.70 2.40 / 2
Minimum weight of rail (calculated) (lb/yd / kg/m)36 / 1833 / 16.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)49 / 124545 / 1143
Boiler Pressure (psi / kPa)200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)14" x 20" / 356x50814" x 22" / 356x559
Tractive Effort (lbs / kg)13,600 / 6168.8616,290 / 7389.03
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.81 3.70
Heating Ability
Tubes (number - dia) (in / mm)177 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m) 9.42 / 2.87
Firebox Area (sq ft / m2)89 / 8.27
Grate Area (sq ft / m2)17.70 / 1.6415.40 / 1.43
Evaporative Heating Surface (sq ft / m2)844 / 78.41729 / 67.75
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)844 / 78.41729 / 67.75
Evaporative Heating Surface/Cylinder Volume236.85185.98
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation35403080
Same as above plus superheater percentage35403080
Same as above but substitute firebox area for grate area17,800
Power L15908
Power MT597.40

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Wes Barris