NZR Q class (1901)

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NZR Q class
NZR Q class
A NZR Q class locomotive
Power type Steam
Builder Baldwin Locomotive Works, Philadephia, Flag of the United States United States
Serial number 19202–19207, 19248–19254[1]
Build date 1901
Configuration 4-6-2
Gauge 1,067 mm (3 ft 6 in)
Driver size 49.125 in (1.248 m)
Wheelbase 48 ft 3.75 in (14.73 m)
Length 55 ft 4.25 in (16.87 m)
Weight on drivers 30.7 tons
Total weight 48.0 tons
Locomotive and tender combined weight 72.1 tons
Fuel type Coal
Fuel capacity 5.0 tons
Boiler pressure 200 psi (1.4 MPa)
Fire grate area 40 sq ft (3.7 )
Cylinders Two
Cylinder size 16 × 22 in (406 × 559 mm)
Tractive effort 18,340 lbf (81.6 kN)
Locomotive brakes Steam
Train brakes Vacuum
Career NZGR
Number in class 13
Number 338-350[1]
Locale Auckland - Rotorua,
Oamaru - Dunedin
First run 1901-12-24
Retired 1957-12-07
Disposition All scrapped

The NZR Q class was an important steam locomotive not only in the history of New Zealand's railway network but also in worldwide railways in general. Designed by New Zealand Government Railways' Chief Mechanical Engineer A. L. Beattie and ordered from the Baldwin Locomotive Works in 1901, they were the first locomotives in the world to be built with the wheel arrangement of 4-6-2. This wheel arrangement came to be known as the Pacific type after the voyage the completed locomotives had to make across the Pacific Ocean to New Zealand. A few instances of the 4-6-2 wheel arrangement are known to have existed prior to 1901, but these were all reconstructions of locomotives that were originally built with a different wheel arrangement, thereby making the thirteen members of the Q class the first "true" Pacifics in the world. The Pacific style went on to become arguably the most famous wheel arrangement in the world.

Contents

[edit] Design

The Q class's design stems from the requirement for a locomotive similar to the Ub class with the inclusion of a wide firebox to burn poor quality lignite coal from the South Island and the Waikato.

[edit] Operation

In operation, the locomotives proved to be satisfactory rather than brilliant and they suffered from occasional gear problems. They were soon displaced from the most important and difficult work by members of the A and AB classes; in fact, later in life, they were re-boilered with AB boilers.

[edit] Withdrawal

They saw out their final years working in Otago and the West Coast and the last Q class locomotive was retired in 1957. Sadly, no examples of the class have been preserved.

The members of this Q class should not be confused with the members of 1878's Q class. As all of the 1878 locomotives had been withdrawn by 1901, the classification was free to be used again.

[edit] External links

[edit] References

  1. ^ a b Q Class 4-6-2 Register. Retrieved on 2008-02-10.
  • Heath, Eric, and Stott, Bob; Classic Steam Locomotives Of New Zealand, Grantham House, 1993
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