NZR X class

NZR X class

Type and origin Power type Steam Builder NZR Addington Workshops Build date 1908 - 1909, 1913 - 1915 1943 - 1949 (rebuild)

Specifications Configuration 4-8-2 Gauge 3 ft 6 in (1,067 mm) Driver diameter 45 in (1.143 m) Length 56 ft 9.75 in (17.32 m) Adhesive weight 46.7 long tons (47.4 t; 52.3 short tons) (original) 45.6 long tons (46.3 t; 51.1 short tons) (rebuild) Loco weight 66.7 long tons (67.8 t; 74.7 short tons) (original) 66.6 long tons (67.7 t; 74.6 short tons) (rebuild) Tender weight 27.3 long tons (27.7 t; 30.6 short tons) (original) 28.55 long tons (29.01 t; 31.98 short tons) (rebuild) Loco & tender weight 94.0 long tons (95.5 t; 105.3 short tons) (original) 95.15 long tons (96.68 t; 106.57 short tons) (rebuild) Fuel type Coal Fuel capacity 4.0 long tons (4.1 t; 4.5 short tons) (original) 5.0 long tons (5.1 t; 5.6 short tons) (rebuild) Water cap 2,200 imp gal (10,000 L; 2,600 US gal) Boiler pressure 230 psi (1,586 kPa) (original) 215 psi (1,482 kPa) (rebuild) Firegrate area 37.1 square feet (3.4 m2) (original) 37.5 square feet (3.5 m2) (rebuild) Heating surface 2,066 sq ft (191.9 m2) (original) 1,185 sq ft (110.1 m2) (rebuild) Superheater:  • Heating 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 in × 22 in (343 mm × 559 mm) Low-pressure cylinder size 22 in × 22 in (559 mm × 559 mm)

Performance figures Maximum speed 30 mph (48 km/h) Tractive effort 26,620 lbf (118.4 kN) (original)/ 31,150 lbf (138.6 kN) (starting) 29,500 lbf (131 kN) (rebuild)

Career Number in class 18 Numbers 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First run 1909 Last run 1957 Retired 1935–1950 Current owner Feilding & Districts Steam Rail Society (1) Disposition Withdrawn, one preserved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 two were sold to the Ohai Railway Board (ORB) that operated a private industrial line at the end of the Wairio Branch.

Class register

Key:	In service	On lease	Out of service	Preserved	Overhaul/Repair	Scrapped

Number	Builder	Entered service	Withdrawn	Notes
439	NZR Addington	9-1-1909	2-3-1957	Converted to 4-cylinder simple, 6-1949
440	NZR Addington	25-3-1909	2-3-1957	Converted to 4-cylinder simple, 7-1948
441	NZR Addington	10-5-1909	2-3-1957
442	NZR Addington	10-7-1909	4-3-1944	Converted to 4-cylinder simple, 6-1943. In Use Ohai Railway Board 1944-1968. Preserved at Feilding and District Steam Rail Society
443	NZR Addington	1-12-1909	2-3-1957	Converted to 4-cylinder simple, 7-1947
444	NZR Addington	3-2-1910	2-3-1957	Converted to 4-cylinder simple, 12-1949
445	NZR Addington	24-5-1910	26-5-1949
446	NZR Addington	30-4-1910	6-12-1946	Converted to 4-cylinder simple, 12-1946. In Use Ohai Railway Board 1946-1959.
588	NZR Addington	14-10-1913	2-3-1957	Converted to 4-cylinder simple, 5-1951
589	NZR Addington	11-11-1949	6-1949
590	NZR Addington	27-1-1914	2-3-1957
591	NZR Addington	17-3-1914	2-3-1957	Converted to 4-cylinder simple, 12-1950
592	NZR Addington	22-6-1914	2-3-1957	Converted to 4-cylinder simple, 10-1950
593	NZR Addington	3-9-1914	2-3-1957	Converted to 4-cylinder simple, 6-1950
594	NZR Addington	31-10-1914	2-3-1957	Converted to 4-cylinder simple, 5-1945
595	NZR Addington	3-12-1914	2-3-1957
596	NZR Addington	26-1-1915	2-3-1957	Converted to 4-cylinder simple, 12-1949
597	NZR Addington	1-4-1915	2-3-1957

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. Two X class boilers are held by Mainline Steam.

References

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

External links

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