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


Class Details by Steve Llanso of Sweat House Media

Class K (Locobase 1108)

See also "The Mud Rogers, the history" at [link] and "The K88 Restoration" at [link], last accessed 28 February 2014. See also Charles Rous-Marten, "The New Zealand Railways 3 ft 6 in Gauge-Their Progress and Results for 1884-Their Locomotive Practice, and New Departures in that Department", No 24575, English Mechanic and World of Science, No. 1,063 (7 August 1885), pp. 499-500; and Charles Rous-Marten, "New Zealand Railways: Their History, Engines and Work", The Railway Magazine (December 1899), pp. 567+. Works numbers were 2454-2455 in 1877, 2469-2474 in 1878.

Eight narrow-gauge engines known on the railroad as Hudson Double Enders, the last of which was retired in 1929. Photos show a long wheelbase for these locomotives, a steam dome over the firebox and the sand dome well forward. She had a very straight line.

Although first described contemptuously as "Yankee toys," according to OS Nock (RWC II, pl 130),"...the enginemen soon found they were capable of hard work, and they became warmly appreciated." This class gave very satisfactory performance. In one instance, a K pulled 90 grain cars and 10 gravel cars (total train load of 700 tons) from Lyttelton to Christchurch. They were also timed at 55 mph (89 km/h) even though the 40-lb (20 kg/metre) rail supposedly restricted speed to 35 mph (56 km/h). Leitch and Sinclair (Trains, September 1983) quote a British railway journalist as saying they looked like watches with all the moving parts on the outside.

Rous-Marten's 1885 report, written when he lived in New Zealand, offered a mixed review. While they operated "admirably" heading light trains on mostly level gradients, the Ks were "not equal to heavy loads on the steeper gradients of 1 in 50 (2%) for many miles, which prevail near Dunedin."

See Locobase 1499 for the later rebuild and one member's restoration to service in the 1980s.


Class K rebuilds (Locobase 1499)

After two decades of service, the Hudson Double Enders were rebuilt to the dimensions shown here and given a Belpaire-type boiler in place of the original wagon top. In the process, her steam dome moved forward. (Leitch and Sinclair (Trains, September 1983) note the original Rogers boilers were still sound enough to be used in stationary engines for years to come.) After the rebuilds, these engines carried on until the late 1920s. K88 (Washington - works #2454) and three other Ks were dumped into the Oreti Estuary to shore up the river bank. In 1974, K88 was exhumed from her not-quite-final resting place and restored with much effort by Bob Anderson, a wool buyer and Secretary of the Plains Railway Museum. She required 10,000 man-hours over 6 years and ran again in November 8, 1981 (formal recommissioning coming a year later).

Principal Dimensions by Steve Llanso of Middle Run Media
ClassKK rebuilds
Locobase ID1108 1499
RailroadNew Zealand Government RailwaysNew Zealand Government Railways
CountryNew ZealandNew Zealand
Whyte2-4-22-4-2
Number in Class88
Road NumbersK-87-K88, K92-K97
Gauge3'6"3'6"
Number Built8
BuilderRogersNRGR
Year18771903
Valve GearStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)11.84 / 3.61
Engine Wheelbase (ft / m)22.24 / 6.78
Ratio of driving wheelbase to overall engine wheelbase 0.53
Overall Wheelbase (engine & tender) (ft / m)39.07 / 11.91
Axle Loading (Maximum Weight per Axle) (lbs / kg)16,579 / 7520
Weight on Drivers (lbs / kg)33,153 / 15,03830,000 / 13,608
Engine Weight (lbs / kg)52,192 / 23,67451,000 / 23,133
Tender Loaded Weight (lbs / kg)43,008 / 19,508
Total Engine and Tender Weight (lbs / kg)95,200 / 43,182
Tender Water Capacity (gals / ML)1500 / 5.68
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 2.40 / 2
Minimum weight of rail (calculated) (lb/yd / kg/m)28 / 1425 / 12.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)49.50 / 125749.50 / 1257
Boiler Pressure (psi / kPa)130.50 / 900160 / 1100
High Pressure Cylinders (dia x stroke) (in / mm)12.01" x 20" / 305x50812" x 20" / 305x508
Tractive Effort (lbs / kg)6465 / 2932.487913 / 3589.28
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.13 3.79
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)
Grate Area (sq ft / m2) 8.82 / 0.8210.10 / 0.94
Evaporative Heating Surface (sq ft / m2)589 / 54.74
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)589 / 54.74
Evaporative Heating Surface/Cylinder Volume224.61
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation11511616
Same as above plus superheater percentage11511616
Same as above but substitute firebox area for grate area
Power L1
Power MT

All material Copyright © SteamLocomotive.com
Wes Barris