The NZR G Class was a class of four saddle tank locomotives from English builders Black Hawthorn in the early 1870s. Like the similarly sized D class, they were an attempt to produce a passenger version of the already highly successful F class.[1]

NZR G Class (1874)
G Class steam locomotive, NZR 55
Type and origin
BuilderBlack, Hawthorn & Co (4)
Build date1873
Specifications
Configuration:
 • Whyte4-4-0T
Driver dia.36 in (0.914 m)
Adhesive weight13.2 long tons (13.4 t; 14.8 short tons)
Loco weight18.2 long tons (18.5 tonnes; 20.4 short tons)
Firebox:
 • Grate area9 sq ft (0.84 m2)
Boiler pressure130 lbf/in2 (0.90 MPa)
Heating surface486 sq ft (45.2 m2)
CylindersTwo, outside
Cylinder size10.5 in × 18 in (267 mm × 457 mm)
Performance figures
Tractive effort4,893 lbf (21.77 kN)
Career
OperatorsNZR
DispositionAll scrapped

Origin and design

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The G class was ordered by the Canterbury Provincial Council. They were derived from the F class, replacing the first of the three driving axles with a four-wheel bogie. It was hoped that the reduced rigid wheelbase would allow the locomotive to provide higher speed passenger services. The type suffered from lack of weight on the driving axles, a driver stating that "it took the 'G' all its time to push its front bogie along, let alone pull a load".[2] They were followed by the L Class which were a more successful attempt to produce a faster F Class.

Service

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In the early 1890s the locomotives were progressively transferred to the Picton section, where it was felt that they had been relegated to get rid of them from the busy Hurunui-Bluff section. Their maximum load on the 1 in 37 gradient from Picton was six 4-wheel wagons.[3]

Withdrawal and disposal

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All of the locomotives were withdrawn between 1915 and 1919 and were sold for further service in industry.

See also

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References

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Citations

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  1. ^ Palmer & Stewart 1965, p. 32.
  2. ^ Millar 2011, p. 108.
  3. ^ Boult, A A (September 1960). "The G Class 4-4-0 tank locomotives". Railway Observer. 85 (reprinted Oct 2017): 160–161.

Bibliography

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