NZR G class (1928)

NZR G class (1928)
A G class locomotive in Garratt form.
Type and origin Power type Steam Builder Beyer, Peacock & Company Serial number 6484–6486 Build date 1928
Specifications Configuration: ​  • Whyte Garratt: 4-6-2+2-6-4 Driver dia. 57 in (1.448 m) Length 84 ft 3.75 in (25.70 m)[1][2] Width 8 ft 6 in (2.59 m) Height 11 ft 6 in (3.51 m) Adhesive weight 87.7 long tons (98.2 short tons; 89.1 t) Loco weight 146.8 long tons (164.4 short tons; 149.2 t) Firebox: ​  • Grate area 58.2 sq ft (5.41 m2) Boiler pressure 200 psi (1.4 MPa) Heating surface 2,223 sq ft (206.5 m2) Cylinders 6 Cylinder size 16.5 in × 24 in (419 mm × 610 mm)
Performance figures Tractive effort 51,580 lbf (229.44 kN)
Career Operators New Zealand Government Railways Number in class 3 Numbers 98–100 First run 1928 Last run 1931 Preserved 0 Disposition Withdrawn

The NZR G class was a type of Garratt locomotives used in New Zealand, later rebuilt as Pacific type locomotives. They were the only Garratt type steam locomotives ever used by the New Zealand Railways (NZR). They were ordered to deal with traffic growth over the heavy gradients of the North Island Main Trunk (NIMT) and to do away with the use of banking engines on steep grades.^[1] They were one of the few Garratt designs to employ six cylinders. A mechanical stoker was used to feed coal into the locomotive.^[1] The locomotives lasted longer in rebuilt form as standard Pacific locomotives than they did as Garratts, but their numerous mechanical issues lead to their final withdrawal following a union ban on their use in 1956.^[3]