NZR X class

NZR X class
Power type	Steam
Builder	NZR Addington Workshops
Build date	1908 - 1909, 1913 - 1915 1943 - 1949 (rebuild)
Configuration	4-8-2
Gauge	3 ft 6 in (1,067 mm) Cape gauge
Length	56 ft 9.75 in (17.3 m)
Weight on drivers	46.7 long tons (47.4 t) (original) 45.6 long tons (46.3 t) (rebuild)
Locomotive weight	66.7 long tons (67.8 t) (original) 66.6 long tons (67.7 t) (rebuild)
Tender weight	27.3 long tons (27.7 t) (original) 28.55 long tons (29.01 t) (rebuild)
Locomotive & tender combined weight	94.0 long tons (95.5 t) (original) 95.15 long tons (96.68 t) (rebuild)
Fuel type	Coal
Fuel capacity	4.0 long tons (4.1 t) (original) 5.0 long tons (5.1 t) (rebuild)
Water capacity	2,200 imp gal (10,000 L)
Boiler pressure	230 psi (1,600 kPa) (original) 215 psi (1,480 kPa) (rebuild)
Firegrate area	37.1 square feet (3.4 m2) (original) 37.5 square feet (3.5 m2) (rebuild)
Superheater area	None (original) 168 square feet (15.6 m2) (rebuild)
Cylinders	2 high pressure + 2 low pressure (original) 4 high pressure (rebuild)
High-pressure cylinder size	13.5 × 22 in (34 × 56 cm)
Low-pressure cylinder size	22 × 22 in (56 × 56 cm)
Top speed	30 mph (48 km/h)
Tractive effort	26,620 lbf (118.4 kN) (original) 29,500 lbf (131 kN) (rebuild)
Number in class	18
Number	439–446 588–597
Locale	North Island Main Trunk
First run	1909
Last run	1957
Retired	1935–1950
Current owner	Feilding & Districts Steam Rail Society (1)
Disposition	Withdrawn, one preserved

The NZR X class was a pioneering class of eighteen 4-8-2 steam locomotives designed by A. L. Beattie that operated on the national rail network of New Zealand. In 1908, a heavy and powerful locomotive was required to haul traffic on the newly completed mountainous central section of the North Island Main Trunk Railway, and as a logical progression of the 4-6-2 Q class design, the 4-8-2 wheel arrangement was created for the X class.

Overview

When the first X was completed in 1908 at NZGR's Addington Workshops in Christchurch, it was the very first 4-8-2 locomotive built in the world. The 4-8-2 design went on to be popular in the United States and was nicknamed the "Mountain" type; one theory suggests this name stems from the mountainous terrain that inspired the X's design, while another suggests the Chesapeake and Ohio Railway first coined the name in reference to its 4-8-2s of 1911 that were built to operate in the Allegheny Mountains.

The X class initially operated as the freight counterpart of the passenger A class, but they struggled to operate at speeds higher than 50 km/h (30 mph). They were built as de Glehn compound locomotives, but during the 1940s, most of the class were converted to simple, superheated locomotives. This increased their power but did not prolong their lives and most were officially withdrawn from service on 2 March 1957, though a few had been taken out of service earlier and one was sold to the Ohai Railway Board (ORB) that operated a private industrial line at the end of the Wairio Branch.

Preservation

The ORB locomotive, X 442, survived and has passed into the hands of railway preservation enthusiasts. It is currently located at the depot of the Feilding and District Steam Rail Society.

External links

• New Zealand Railways Steam Locomotives - Class X
• An X class locomotive ex-Petone Workshops with a new superheated boiler c1928

References

• Heath, Eric, and Stott, Bob; Classic Steam Locomotives Of New Zealand, Grantham House, 1993