NZR J class (1939)

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NZR J class
J1211 Napier 20Oct2002 JChristianson.jpg
J 1211 being serviced before departure from Napier. Photo by Joseph Christianson
Type and origin
Power type Steam
Builder North British Locomotive Works, Glasgow, Scotland
Build date 1939
 • Whyte 4-8-2
Gauge 3 ft 6 in (1,067 mm)
Wheel diameter 54 in (1.372 m)
Wheelbase 34 ft 10 in (10.62 m)
Length 66 ft 11 in (20.40 m)
Adhesive weight 44.45 long tons (45.16 t; 49.78 short tons)
Loco weight 68.55 long tons (69.65 t; 76.78 short tons)
Tender weight 40.35 long tons (41.00 t; 45.19 short tons)
Total weight 108.9 long tons (110.6 t; 122.0 short tons)
Fuel type Coal [1]
Fuel capacity 6.0 long tons (6.1 t; 6.7 short tons)
Water cap 4,000 imp gal (18,000 L; 4,800 US gal)
 • Firegrate area
39.0 square feet (3.6 m2)
Boiler pressure 200 psi (1,400 kPa)
Feedwater heater ACFI
Heating surface 1,469 square feet (136.5 m2)
 • Heating area 283 square feet (26.3 m2)
Cylinders 2
Cylinder size 18 in × 26 in (457 mm × 660 mm)
Valve gear Baker
Performance figures
Tractive effort 24,960 lbf (111.0 kN)
Number in class 40
Numbers 1200 - 1239
Locale All of New Zealand
First run 1939 - 1940
Last run 1964 - 1967
Retired 1964 - 1971
Scrapped 1969 - 1971
Current owner Ian Welch, Steam Incorporated
Disposition Three preserved, twelve rebuilt as JB, remainder scrapped

The NZR J class steam locomotives were a class of locomotive used in New Zealand. Following the success of the K class on NZR main lines, there was an urgent need for a modern, powerful locomotive capable of running over secondary lines laid with lighter rails. Thus a new "Mountain" 4-8-2 type locomotive was designed and classified by NZGR as the new class J. The 40 locomotives were all built by North British Locomotive Works, Scotland. They should not be confused with the members of 1874's J class, the first tender locomotives to operate in New Zealand. 30 Js were initially allocated to the North Island, the other 10 to the hilly Dunedin-Oamaru section in the South Island where with Wab tank banker engines they provided extra power for wartime freight and passenger loads. By 1950 with a large number of Hillside JA in service the South Island allocation of J and Wab tanks had been returned to Auckland.

The class had a notable appearance with the boiler being partly streamlined after the style of the New Haven Railroad's J400 class, and was also similar to the Norfolk and Western Railway class J and the NSWGR 38 class. The J class incorporated all the latest ideas of the KA class but a noteworthy departure was the use of the Baker valve gear. The tender was of the Vanderbilt type.

Twelve J class locomotives were converted to oil burning and reclassified as JB class, and the bullet nose streamlining was gradually removed. In 1962 ten J were transferred back to the South Island to replace the A class on the steep Greymouth-Otira section and another 6 Js were transferred in the mid 1960s to the SIMT. Some J class locomotives were reboilered with boilers transferred from the first North Island JA withdrawals in 1964-66 and others from the remainder of 12 JA boilers supplied by North British in 1954 for the construction of the last ten Hillside JA. The first reboilered J was used on the Otira route while the rest were reboilered in 1967. J 1236 was refitted with JA 1281's boiler,[2] and second NI JA boiler was approved for refitting to a J in mid 1967,[3] 2 spare JA boilers were supplied with the delivery of the boilers, from North British, Glasgow for the last 10 JA to Hillside in 1953-54 and there was some swapping of boilers between JAs 1240 receiving JA 1255 boiler and J 1200 driving wheels in 1966 [4] The three J engines that were used with the JA class on the South Island Limited in its last years in 1969-70 and later preserved were effectively a new 'JC' class with JA boilers and North Island JA tenders, reconstructed for coal rather than oil supply and had North Island JA trailing trucks, under the cab. The original J had been mainly freight and banking engines on the NIMT and had only powered a few provincial passenger trains, the Opua Express, the Auckland- New Plymouth night express and the Tanetua express. J 1211 and J1234 with JA 1267 were the usual engines on the fast South Island Limited on the Christchurch-Oamaru section, in its last year, their 'JC' conversion having made them NZRs final mainline steam flyers.

JB class[edit]

The NZR JB class steam locomotives were all originally members of the NZR J class of 1939. Built by North British Locomotive Works, Scotland, they all initially burned coal and wore distinctive bullet-like streamlining. After World War II the railways suffered problematic coal shortages, especially in the North Island. Approval was gained to convert 12 of the J class locomotives into oil-burners, to burn heavy fuel oil which was available in plentiful quantities at the time. The conversion saw the installation of a two-nossle burner in the firebox, removal of the grate and ashpan which was replaced with a firepan lined with bricks, shortening of the superheater tubes in the boiler, removal of the spark arrester in the smokebox, removal of the brick arch, addition of the related controls and gauges for the oil burning equipment, and the tender modified to carry an oil bunker and associated steam piping. Similar to the K and KA Classes which were converted to oil burning at the same time, the JB Class utilized a separate, removable tank which sat in the former coal space. However, the full-width coal bunker of the J-type's Vanderbilt tender was cut down so that the oil tank was visible at the sides, with distinctive vertical supports below. The conversion process generally coincided with the removal of the streamlining, but not always. Once converted, the locomotives were re-classified JB in recognition of the conversion, however they retained their original J class numbers.

The JB Class in service[edit]

In service the JB class performed well, but did not distinguish themselves above the unconverted J class nor any of the other J variants. Some of the JB Class received cross-compound Westinghouse pumps in place of the twin single-phase pumps, but others did not. The JB Class only ever saw service in the North Island, as in the South Island coal supplies were plentiful. Some years after conversion to oil, the fuel oil being used became considerably dearer than the coal supplies then being sourced, and there was no longer a coal shortage. However re-conversion back to coal burning did not occur due to objections from the various railway Unions.

Withdrawal and disposal[edit]

Some members of the JB Class were among the first of the J 4-8-2 types to be withdrawn, due to the faster wear and tear suffered by the locomotives as a result of oil burning. The last of the class was withdrawn from service by March 1968, by which time steam haulage in the North Island had essentially finished anyway.[5] All of the class were scrapped, although many items from the locomotives were retained as spares for the other J type locomotives still in service in the South Island.


No JB class locomotives were preserved, although the tender from JB 1203 is held by Steam Incorporated. In addition, preserved J class locomotive No. 1236 has been restored as a JB class oil burner by its owners Mainline Steam, although this particular locomotive spent its entire NZR career as a coal-burning J Class.[6] Preserved locomotive J 1211, also owned by Mainline Steam, has been converted to oil burning in the same manner as the JB class, but has not been re-classified to reflect that change.

Preserved Locomotive List[edit]

Class register[edit]

Key: In service On lease Out of service Preserved Overhaul/Repair Scrapped
Number Builder Entered service Withdrawn Notes
1200 North British October 1939 July 1964 Converted to an oil burner and reclassified as JB 1200.
1201 North British October 1939 July 1969
1202 North British October 1939 April 1966
1203 North British November 1939 October 1964 Converted to an oil burner and reclassified as JB 1203. Tender held by Steam Incorporated.
1204 North British November 1939 January 1966
1205 North British November 1939 October 1967 Converted to an oil burner and reclassified as JB 1205.
1206 North British November 1939 May 1965 Converted to an oil burner and reclassified as JB 1206.
1207 North British November 1939 April 1966
1208 North British November 1939 July 1969
1209 North British November 1939 July 1969
1210 North British December 1939 March 1969
1211 North British December 1939 November 16, 1971 Preserved, Mainline Steam. Converted to an oil burner, 1995.
1212 North British December 1939 July 1969
1213 North British December 1939 December 1967 Converted to an oil burner and reclassified as JB 1213.
1214 North British December 1939 January 1965
1215 North British January 1940 January 1965
1216 North British January 1940 July 1969
1217 North British January 1940 March 1969
1218 North British January 1940 April 1967 Converted to an oil burner and reclassified as JB 1218.
1219 North British January 1940 April 1966
1220 North British February 1940 January 1966
1221 North British February 1940 May 1966
1222 North British February 1940 January 1965
1223 North British February 1940 January 1966
1224 North British February 1940 August 1967 Converted to an oil burner and reclassified as JB 1224.
1225 North British February 1940 January 1966
1226 North British February 1940 July 1969
1227 North British February 1940 March 1969
1228 North British March 1940 March 1968 Converted to an oil burner and reclassified as JB 1228.
1229 North British March 1940 January 1965 Converted to an oil burner and reclassified as JB 1229.
1230 North British March 1940 October 1964 Converted to an oil burner and reclassified as JB 1230.
1231 North British March 1940 July 1969
1232 North British March 1940 July 1969
1233 North British March 1940 December 1967 Converted to an oil burner and reclassified as JB 1233.
1234 North British March 1940 November 16, 1971 Preserved, Steam Incorporated. J 1234 was on loan to the Glenbrook Vintage Railway, 1998. Returned to Steam Incorporated over the weekend of 6–7 June 2015.
1235 North British March 1940 September 1967
1236 North British March 1940 November 16, 1971 Preserved, Mainline Steam . Converted to an oil burner and reclassified as JB 1236, 2001.
1237 North British March 1940 March 1969
1238 North British March 1940 February 1967
1239 North British March 1940 March 1968 Converted to an oil burner and reclassified as JB 1239.


  1. ^ Oil-burning J class locomotives were classified JB. Restored J class locomotive 1211 Gloria originally burned coal, but was converted to oil-burning during restoration. Oil capacity is 1,350 imp gal (6,100 L; 1,620 US gal).
  2. ^ J. Evans . The story of Mainline Steam. Mainline Steam Heritage Publishing (2013)p 63
  3. ^ NZ Nat Archives files JA/DJ. Wgtn
  4. ^ J. Evans. The Story of Mainline steam (2013),p67
  5. ^ Register of New Zealand Steam Locomotives, W.G. Lloyd
  6. ^ The Locomotives of the Mainline Steam Trust, by Graeme Moffatt

External links[edit]