NZR N class

NZR N class

NZR N class in service for the Wellington and Manawatu Railway Company as number 9, c. 1900.
Type and origin
Power type Steam
Builder Baldwin Locomotive Works
Build date 1885, 1891, 1901
Specifications
Configuration 2-6-2
Gauge 3 ft 6 in (1,067 mm)
Driver diameter 49.125 in (1.248 m)
Length 50 ft 2 in (15.29 m) (1891 batch)
Adhesive weight 21 long tons (21 t; 24 short tons)
Loco weight 31.8 long tons (32.3 t; 35.6 short tons)
Tender weight 19.0 long tons (19.3 t; 21.3 short tons)
Loco & tender weight 50.7 long tons (51.5 t; 56.8 short tons) (1891 batch)
Fuel type Coal
Fuel capacity 7.5 long tons (7.6 t; 8.4 short tons)
Water cap 5,000 imp gal (23,000 l; 6,000 US gal)
Firebox:
 • Firegrate area		 16 sq ft (1.5 m2)
Boiler pressure 135 psi (931 kPa) (1891 batch)
Heating surface 853 sq ft (79.2 m2)
Cylinder size 15 in × 20 in (381 mm × 508 mm)
Performance figures
Maximum speed 103.6 km/h (64.4 mph)[1]
Tractive effort 9,890 lbf (43.99 kN)
Career
Operators Wellington and Manawatu Railway (2), New Zealand Government Railways (10)
Number in class 12
Numbers 27, 30, 34, 36, 37, 42, 351-354, 453 (ex WMR No. 9), 454 (ex WMR No. 10)
Locale Auckland, Hawke's Bay, Wellington (both NZR and WMR lines), Wairarapa, West Coast
Retired November 1926 - March 1934
Current owner Wellington and Manawatu Railway Trust
Disposition Withdrawn, one preserved

The N class were 12 steam locomotives that operated on the national rail network of New Zealand. They were built in three batches, including one batch of two engines for the private Wellington and Manawatu Railway Company, the WMR, by the Baldwin Locomotive Works in 1885, 1891, and 1901. Previously the N class designation had been applied between 1877 and 1879 to Lady Mordaunt, a member of the B class of 1874.[2]

Construction

Despite the Long Depression of the 1880s, the young New Zealand railway network continued to expand and additional motive power was required. The New Zealand Railways Department had normally ordered locomotives from England up until this time, though it had previously bought locomotives from United States manufacturers (such as the Rogers K class), and in 1885 it placed an order with Baldwin, whose first New Zealand locomotives were the T class, to construct the six original members of the N class, which entered service between October and December 1885.

Six years later the WMR required additional motive power to handle the growing traffic on their line from Wellington to Longburn, just south of Palmerston North. Its typical supplier of equipment was Baldwin, who offered the WMR a locomotive similar to the N class. The WMR ordered two such locomotives and they entered service as Nos. 9 and 10. They proved to be more efficient than the 1885 batch, and in an attempt to match these efficiencies the government converted N 27 into a Vauclain compound, but with little success.

In 1901, the government ordered four similar locomotives.

Subclasses

Two sub-classes of the N class existed, both Baldwin Vauclain compounds built for the WMR. Nos. 14 and 15 were a heavier and more powerful version of the N class and became the NA class; Nos. 5 and 18 had wider fireboxes and became the NC class.

Operation

The 1885 batch operated in the Hutt Valley and the Wairarapa, the 1901 batch around Auckland. In 1908 the WMR was nationalised and incorporated into the government's network. The two ex-WMR Ns continued to work on their home route until World War I, when they were transferred to Westland to operate the mail trains between Greymouth and Otira, making full use of their speed. In the 1920s the two were modified for shunting duties, including the addition of a tender cab and side ladders on the tender.

A world record

The most outstanding operational feat by an N class locomotive occurred on 20 July 1892. WMR No. 10 departed Wellington with a special test train, and gradually picked up speed on the flat trackage of the Kapiti Coast and Horowhenua. It ran comfortably at speeds of 50-55 mph, and between Levin and Shannon it reached 64.4 mph (103.6 km/h), then the world speed record on 3 ft 6 in (1,067 mm) narrow gauge track.

Withdrawal

By the 1920s withdrawal was seriously considered. The first two were withdrawn in November 1926; the boiler from WMR No. 9/N 453, withdrawn on 13 November 1926, was re-used on WB 300 when it was overhauled, distinguishing it from others of its class. Three more were withdrawn in March 1927, and N 27, the first member of the class, followed in November of that year. Record-setting WMR No. 10/N 454 was also meant to be withdrawn in 1927 but was given a reprieve: its crews formally complained about its poor condition and it ceased service on 30 January 1928. It was stripped of useful parts and sat in Greymouth yard until it was officially written off on 31 March 1928. It was dumped in the Waimakariri River as a means of stabilising the riverbank. The last N was taken out of service in March 1934.

Preservation

None of the N class were saved for preservation - they were withdrawn at least two decades before the preservation movement had even seriously begun. However, the skeleton of WMR No. 9/N 453 was discovered near Arthur's Pass, dumped in the Bealey River, and it was recovered by the Wellington and Manawatu Railway Trust in stages between 2003 and 2006 with the aim of restoring it to full operational condition. On 27 February 2007, No. 9 returned to its old home of Paekakariki and is now based at the depot of Steam Incorporated, where it is undergoing restoration to working order.

By May 2009, No.9's tender had been dismantled, and the frames and bogies overhauled and reassembled.

Railway enthusiasts have also attempted to find the remnants of WMR No. 10/N 454 but have not yet had success.

Class roster

Key: In service Out of service Preserved Overhaul/Repair Scrapped
NZR
Road
number 		Builder Builders
number 		WMR
Number 		In
service 		Written
off 		Comments
27 Baldwin 7576 30-10-1885 6-6-1927 Rebuilt as Vauclain compound in 1895.
30 Baldwin 7571 12-11-1885 27-7-1933
34 Baldwin 7575 10-11-1885 27-1-1933
36 Baldwin 7579 10-11-1885 1-3-1929
37 Baldwin 7573 9-12-1885 11-1926
42 Baldwin 7574 9-12-1885 3-1934
351 Baldwin 19270 20-11-1901 31-3-1927 Dumped at Westfield
352 Baldwin 19271 18-11-1901 27-8-1929 Dumped at Westfield
353 Baldwin 19272 22-11-1901 31-3-1927 Dumped at Westfield
354 Baldwin 19273 22-11-1901 31-3-1927 Dumped at Westfield
453 Baldwin 12104 9 1-1892 13-11-1926 Dumped in the Bealey River, 1926. Retrieved 2003. Preserved by Wellington and Manawatu Railway Trust, Paekakariki.
454 Baldwin 12106 10 1-1892 7-3-1928 Dumped in the Waimakariri River, 1928.

See also

References

  1. ↑ On 20 July 1892, then a world record on 3 ft 6 in (1,067 mm) gauge track
  2. ↑ Sean Millar, From A to Y Avoiding I: 125 Years of Railway Motive Power Classification in New Zealand (self-published, 2001, ISBN 0-908726-28-7), 59.

External links

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