Tuesday, 13 October 2015

West Coast Rail Trail Ruatapu-Ross opening 24 October

So while some people are jaunting round the South Island by steam train, another kind of rail event will be happening with the opening of the section of the West Coast Rail Trail from Ruatapu to Ross.

This section incorporates many of the old wooden bridges that were built along this section of the railway which was constructed in the early 1900s. The biggest of these is the 1909 bridge crossing the Totara River just north of Ross.

This shows the last set of piles being driven on the bridge. It is a Howe Truss, which was a popular style of wooden bridge in that era, but is not a well known style today. Based on the above picture and the aerial from Google I would guess there are six spans of the bridge and if they were 80 feet in length which is one of the standard lengths the railways used for Howe Truss spans, then that would make this bridge 480 feet or 145 metres in length. Not the longest around but as a bridge that is just not seen almost anywhere any more, especially on the coast since the demise of the combined bridge at Arahura and the Grey River rail bridge at Cobden, it is pretty special and even more so that it has survived 35 years since the branch line closed. (AUCKLAND WEEKLY NEWS PHOTO FROM AUCKLAND LIBRARIES)

Inspecting the bridge prior to starting work (LIDDELL CONTRACTING PHOTO). Here you can see one of the pile sets in the river bed and the bridge itself with two of the Howe Truss spans. Most of the bridges survived because the section was used as an access track and even while the rails stayed in place for a few years after closure the locals made their own rail-capable vehicles (jiggers) to run on the rail section. I still have a clipping from the newspaper in the late 1980s when tenders were finally called to lift this last section of the railway, and obviously it was lifted but the bridges were left in place. One of the issues for the railways was the high cost of maintaining these bridges. The much larger bridge combined bridge at Hokitika which was partly in Howe truss and partly open spans, was the cause of closing the line in 1980 because the maintenance cost was too much.

Google Earth shot of the bridge last year and as you can see from the red line their rail trail visitor (this trace is from the actual official NZ Cycleway website and is shown on a map as the actual route) has had to take a big detour through the river bed to get across the river at this point. So everyone will love the fact the bridge is getting fixed up for the cycleway.

A Whites Aviation aerial of the Ross railhead in 1951. The route chosen for the railway put the station nearly 2 km from the outskirts of the township so typical aerials of the Ross township will not show the railway yard. Even today there is still not a lot there and in fact a lot less these days as apart from the railway station buildings, the engine depot and the houses which all became surplus to requirements in 1980, the sawmill next to the station with its own houses has also disappeared, although on the south side of the road there is still a timber yard where the one can be seen in the photo.

With the amount of aerial shots I am digging up these days then at some point it will be interesting to dig up one of Ross yard, anyway a few details can be filled in from this Google Earth one and the previous one. The road is still in much the same place running along the edge of the station yard then coming in close to the railway about where the settlement was so that gives some perspective. Just at the end of the settlement was the engine depot and one of the features still visible today is where the triangle was for turning engines as marked out above.

Taken at the same time as the photo of the Totara River bridge above, this one shows the railway station almost complete at that point. In the distance you can see the engine shed, water vat and a windmill that must have been used to pump up water for the vat. The houses which can be seen to the right past the station would have taken their water supply from the same vat probably. (AUCKLAND WEEKLY NEWS PHOTO)

LIDDELL CONTRACTING photo of the bridge, a closeup showing some construction details. You can see the steel beam and the rods that were about the only metal components in a Howe Truss. The wooden components of the bridge are very visible and these were the parts that needed a lot of maintenance and specialised work and also the problem in many of these old bridges was pile foundations in the fast flowing riverbeds where scour could wash away the bed they were driven into making them very weak and prone to collapse. This sort of problem happened a lot at Ngahere where the Grey River was crossed by a very long Howe Truss bridge for the Blackball Branch and where basically a poor decision to make this bridge in wooden piles instead of the large steel cylinders used on some of the other bridges driven deep into the river bed meant it was washed out in just about every flood down the Grey. When wooden piling was in vogue the piles would not be driven as deep as the foundations go today in many cases. But for the iron cylinders filled with concrete at a number of locations, the construction technique was quite different as the river bed was excavated to sink the cylinder down into it. 

LIDDELL CONTRACTING photo from a crane overlooking the bridge. I would guess the old wooden beams supporting the rail track have been taken off the bridge and two new runners put down to support the cycleway deck as we can see here. When the bridges were built for rail the sleepers and track were actually a structural component of the deck and helped to hold the bridge together. As the roading powers that be would find sometimes when a combined bridge was handed over by the Railways after they had built a new bridge alongside, removing the track off the old bridge was not such a good idea if the bridge became weaker.

LIDDELL CONTRACTING photo of one of the more common bridges between Ruatapu and Ross. I presume these are sleepers but I am unsure of the longer ones unless there was a walkway alongside one side of the bridge. A look on Google will show us at least six of these bridges in the section.

LIDDELL CONTRACTING photo of the completed deck on one of these bridges. One of the issues for the area is that prospecting surveys have been done that show there are appreciable quantities of gold around this coastal strip where the old railway ran and the possibility that the area could be mined in the future cannot be ruled out.

Anyway we look forward to the opening in a couple of weeks of this rail trail.