Saturday 24 December 2011

Catlins River Branch

The coverage of South Otago (which I define as being south of Dunedin, up to the boundary of Southland) has recently considerably improved in Google Earth. This has led to improved maps, particularly the Catlins River branch and the Roxburgh branch, which will be covered separately. For the purposes of this article the maps will be divided into the sections between stations. The positions of stations is largely approximate based on the Quail Atlas. The coverage is so much better that virtually the whole map has been redrawn. The only part unchanged is the junction to near Finegand as this is still medium res Spot coverage.

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Finegand is the first station on the branch and the terminuse of the short stub remaining today. The freezing works has several sidings and is the main reason why this part of the line remains open today.


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The next station is at Otanomomo near the crossing of Kaka Point Road. It is an unremarkable section with the main point of interest being the extant bridge over the Waitepeka River just north of Koau Road, shown as a green arrow near the top of this map.

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Third station is Romahapa which is the effective end of the flat/straight plains initial section of the line. A couple of small bridges remain in place as indicated by some of the green arrows seen north of the main highway crossing.

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The line then climbs relatively gently over the next 6.5 km to Glenomaru (2nd location) which is 51 metres higher in altitude. Curves were no sharper than 9 chains on this route and the most significant grade was about 1 km of 1 in 66 with an average grade of half that. At least four bridges are still in place on this section.

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The section between Glenomaru II and the Hunt's Road station which is seen just below a horseshoe curve at bottom left, contained the Hunts Road tunnel (triangle symbol) with the original Glenomaru station site just to its north. These days you can walk through the tunnel with the italic letter i indicating the public access route from the highway. The tunnel was the summit of a climb on both sides, 1.5 km of 1 in 62 from the north and 1 in 50 for almost 2 km from Hunts Road on the south side.

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From Hunt's Road to Tahora is relatively unremarkable except for the triple horseshoe curves used to get a reasonable grade of 1 in 50 downhill most of the way.

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South of Tahora the route is very nearly straight and level through to the major township of Owaka, the initial terminus, which lost this status after 8 years when the next part opened. It is slightly under halfway.

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Ratanui is alongside the Catlins River estuary (the so called lake) and is reached by way of a gentle ascent and descent of a modest summit halfway from Owaka.

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Grades are also very favourable in the next section to Houipapa.

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Reaching Tawanui requires almost 3 km of continuous ascent at 1 in 66. The station itself gives a short respite in the middle of the long climb to Puketiro.

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South of Tawanui the line ascends 86 metres in 6 km, the uncompensated initial gradient being 1 in 66 over the first half of this distance, and 1 in 55 when compensated for the effects of numerous 7 1/2 chain curves over the remainder. Puketiro is at the summit, and the highest station on the line at 157 metres.

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The entire section through to Caberfeidh is taken up with a descent at a compensated gradient of 1 in 44, again with numerous 7 1/2 chain curves.

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The descent continues at a steeper 1 in 40 compensated grade down to Maclennan from where it levels out. Stuarts station is seen to the far left. A bridge site of about 20 metres length is just north of Maclennan.

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As well as levelling out, the line straightens as well. About halfway between Stuarts and Takahopa was the site of Campbells Siding.