Seddonville Branch

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The Seddonville Branch, now truncated and operating as the Ngakawau Branch, is a branch line railway in the West Coast region of New Zealand's South Island. Construction of the line began in 1874 and it reached its final terminus at the Mokihinui Mine just beyond Seddonville in 1895. Since 1981, it has been closed past Ngakawau and the operating portion effectively functions as an extension of the Stillwater - Westport Line.

[edit] Construction

The Seddonville Branch was built for one reason: the transportation of coal from mines to the harbour in Westport. Unlike most other railways of the era, there was no expectation that the line would open up country for settlement and farming as the terrain was mountainous and not suited to any settlement of significant size.^[1] Coal had been discovered on the north bank of the Waimangaroa River on 25 March 1873, and on 3 March 1874, tenders were called for the construction of a railway to link Waimangaroa with Westport so the coal could be exported. Construction began soon after, and the first section of the line opened to Fairdown on 31 December 1875. Waimangaroa itself was reached on 5 August 1876 and regular services began operating. The next year, an extension to Ngakawau was opened on 12 September 1877, bringing the line's full length to 29.98 kilometres. ^[2]

The impact of the Long Depression limited the government's funds available for railway construction, and accordingly, no extension of the line occurred for over a decade. By the end of the 1880s, New Zealand's economic position was improving and work commenced on extending the line to Seddonville. On 8 August 1893, it opened to Mokihinui, and on 23 February 1895, the New Zealand Railways Department acquired a private line that had been built from Mokihinui through Seddonville to the Mokihinui Mine run by the Mokihinui Coal Company. Some of the funds for the construction of the Ngakawau-Mokihinui section as well as the purchase of the 6.2 kilometre long Seddonville line were provided by the Westport Harbour Board.^[3]

[edit] Stations

The following stations are or were located on the Seddonville Branch (in brackets is the distance from Westport):^[4]

• Sergeants Hill (5 km)
• Fairdown (10 km)
• Waimangaroa (15 km) - junction with the Conns Creek Branch, 1877-1967.
• Birchfield (20 km)
• Granity (27 km)
• Ngakawau (30 km)
• Hector (31 km)
• Nikau (39 km)
• Summerlea (40 km)
• Mokihinui (42 km)
• Seddonville (45 km)
• Mokihinui Mine (48 km)

[edit] Operation

[edit] Passenger services

Passengers on the Seddonville Branch were never served by dedicated passenger trains due to the low population along the route. Instead, the Railways Department operated mixed trains; freight trains with passenger carriages attached. For a period, the mixed trains ran all the way to Mokihinui Mine, but on 12 June 1933, they were cancelled beyond Seddonville. Services to Seddonville lasted another thirteen years, but on 14 October 1946, all passenger provisions on Seddonville Branch trains were removed.^[5] After this point, the only passenger trains on the line have been infrequent enthusiasts' excursions.^[6]

[edit] Freight services

In the first half century of the line's existence, freight was not confined to coal. However, as road transport became more prevalent, local businesses abandoned rail cartage and coal was virtually the only freight carried on the line by the late 1930s. Coal tonnages were declining by this stage too: in 1940, the line was carrying just over half of what it had carried at a pre-World War I peak of 800,000 tons.^[5] Nonetheless, coal traffic was more than sufficient to keep the line in service. An early 1967 timetable featured, every weekday, one train to Seddonville and the Mokihinui Mine and two to Ngakawau along with shuttles from the Conns Creek Branch that diverged from the Seddonville Line in Waimangaroa. However, traffic from the Conns Creek Branch was declining and it closed later that year.^[3]

In the 1980s, traffic significantly rose despite the closure of the line beyond Ngakawau and trains ran not to Westport, but all the way across the South Island via the Midland Line to the deepwater harbour in Lyttelton. In 1981, only 117,000 tonnes of coal were carried to Lyttelton; by 1989, this had risen to 600,000 tonnes. Due to the boom in traffic, new bogie coal wagons were built to replace aging four-wheeled stock of much lower capacity.^[3] In mid-June 2007, traffic was sufficient to justify five trains daily to Lyttelton.^[7]

[edit] Motive power

In September 1875, three steam locomotives were shipped to Westport in readiness for the opening of the line to Fairdown. They were 0-4-2T tank locomotives of the C class. It soon became apparent that greater motive power was required, and in 1898, four W^B class tanks were delivered. Three decades later, they were followed by a number of W^W class tanks, the first of which arrived in 1929, and they were the mainstay of the Seddonville Branch until dieselisation.^[3] However, the W^Ws were somewhat limited on the steep 1 in 33 gradient beyond Seddonville to the Mokihinui Mine and were only capable of hauling a maximum of 180 tons per train.^[8] Occasionally, other steam locomotives operated on the line, including tender locomotives of the U^C class.^[9]

In late 1967, dieselisation began in earnest on the Seddonville Branch with the arrival of DSC class and DJ class diesel locomotives.^[10] A year later, W^W class motive power had been largely replaced by DSCs beyond Waimangaroa.^[11] By mid-1969, steam power had wholly come to an end on the branch, and DJ class locomotives, joined by the DC class in the 1980s, became the predominant source of motive power.^[3] With the de-electrification of the Otira Tunnel on the Midland Line in the latter half of the 1990s, motive power changed to powerful DX class locomotives specially modified to operate through the tunnel.^[11]

At the end of their working lives, some locomotives and rolling stock were used to protect the route of the Seddonville Branch from river erosion. At separate times during 1958 and 1960, two withdrawn W^B class tank locomotives, numbers 292 and 299, were dumped on the bank of the Mokihinui River to ensure the stability of the branch's formation between Seddonville and Mokihinui Mine.^[12]

[edit] Closure past Ngakawau

The three kilometre section beyond Seddonville to Mokihinui Mine closed on 10 February 1974 after the mine itself closed.^[5] Low demand for Buller region coal, decreased output, and a decline in coastal shipping services to Westport meant that the remainder of the line carried reduced tonnages. Closure beyond Ngakawau was proposed in 1976, and although it operated a few more years, maintenance costs were increasingly higher than revenue on the Seddonville section and the line closed on 3 May 1981 with Ngakawau established as the new terminus.^[3]

Some remnants of the line beyond Ngakawau remain. Much of the line's formation remains visible, including embankments, cuttings, and culverts. Part of the old formation near Seddonville has been converted into the Chasm Creek Walkway and it uses two bridges and one tunnel of the former railway. The platform edge of Seddonville station also remains, but the line beyond to the Mokihinui Mine is now largely inaccessible as it is not near any roads.^[13] Nonetheless, in 1989, the Baldwin Steam Trust ventured into this area and recovered W^Bs 292 and 299 with the aim of restoring them to full operational condition.^[14]

[edit] References