Friday, 7 July 2017

Main North Line [2]: Ferniehurst-Claverley

Last post we had a look at Parnassus as the first station within the ambit of the aerial photography that we have as a result of the earthquake in November 2016. There are two main goals to be served by making use of that aerial photography: mapping out all railway features in greater detail, and documenting some of the damage caused by the earthquake. By the time these maps are published the MNL should be open again. Whilst I could use Linz aerials to document the entire line I will not have time to remap any other parts of the MNL so it will just have to do as far as the whole maps project goes.

As we go north from Parnassus I have found this realignment of the MNL between the 137 and 138 km pegs. This was done like much of the other realignment works found on many lines, on the basis of land boundaries on a curve being further out than the current alignment of the railway. Having previously identified many other realignments, particularly several between Nonoti and Phoebe, this is a new one between Parnassus and Ferniehurst.

The curve and gradient diagram for this area says that these two curves as they are today have a radius of 240 metres each. The originals may have been as sharp as 150 metres radius (I don't have any corroboration of this) and would have therefore had a fairly significant limit on train speeds.

From there the next major point of interest is the Hawkswood Bridge. The original structure here was a single lane overbridge. The current overbridge (like many these days a large steel culvert with earth fill embankment over the top) was constructed as part of a highway realignment project in 1999 or 2001. The overbridge sustained significant damage in the quake and repairs have only just been completed at the time of writing.

See this post on Enzed Transport about the highway re-alignments in the area.

 This photo shows the section of highway that was bypassed. This area is still a local road into the settlement of Hawkswood. The highway was winding, narrow and steep at this location.

The next thing north is Ferniehurst at 143.27 km. It used to be much closer to the highway than is the case today because another realignment knocked out some more sharp curves, probably at around the same timeframe as Hawkswood. In this case part of the former highway has been dug up and ploughed into farmland, which is much more commonly seen today than would have been the case in the past, in fact the Resource Management Act probably makes NZTA obligated to remove former roads off the face of the earth. Unlike Parnassus, Ferniehurst stayed open to the public until 1988. It is 10 km north of Parnassus. Spotswood is the station 4 km south of Parnassus that closed in 1978, and Mina a further 10 km south of Spotswood. Mina stayed open to freight until 1987 (the Coastal Pacific still stopped for passengers for a few more years after this). So from the period of closing Spotswood and Parnassus, freight in the area must have been expected to be handled by Mina and Ferniehurst. I would say by 1987 it was pretty clear that the railways wasn't going to hang on to a lot of freight in these small rural areas and the Booz Allen Hamilton report was being implemented in force so there were a lot less stations staying open. Subsequently Rangiora became the first freight centre south of Kaikoura. Mina stayed as a loop, as did Spotswood, Parnassus and Ferniehurst, but with the further rationalisation of service facilities, only Spotswood and Ferniehurst are loops today. 

Ferniehurst also has an old siding still in place as do many of these stations, with the points still in place off the loop.
In this case the siding track which is still in the ground is covered by ballast for loading, so the track has been disused many years and it would seem ballast trains are loaded in the loop, although this blocks out the loop for freight train crossings during loading. Just north of Ferniehurst is Bridge 89 crossing the Conway River.

This is Bridge 90 which is the next one north from the Conway River. It is about halfway between 148 and 149 km. You can see obvious damage at the approaches. The bridge itself was badly damaged and was completely demolished and replaced by a temporary bridge, a permanent bridge is to be built in future.

Hundalee, the next station north at 152.05 km, dates from 1943 with the push through the middle to finish the MNL during WW2, and was closed to traffic in 1981. The station building stayed on the ground until the early 1990s when it was sold and relocated to Waikari to become the terminus of the Weka Pass Railway. Their other station building, at Waipara (named Glenmark) came from Mina in the mid 1980s. The highway between Ferniehurst and Hundalee used to be really twisty but has been straightened out with the realignments around 20 years ago at places called Glen Colwyn and Siberia Ford. Hundalee is where the highway crosses the Conway River (that the railway crossed at Ferniehurst) so that between the two stations the railway and highway are on opposite sites of the river. I remember the Conway River highway bridge being replaced in the mid 1980s. At Hundalee the highway and railway split and they follow completely different routes north and don't meet again until Oaro.

Next station up is Claverley at 157.75 km. This is actually the first point north of Christchurch where the Main North Line runs along the coast. This was the route chosen to put the railway north of Parnassus because the construction was expected to be cheaper and easier than the inland route (which even today is pretty challenging as is clear from some of the repairs needed on the Inland Highway). 

Claverley is another station that dates from the 1940s and had a quiet life until closing to public traffic in 1981 but was retained as a loop. There is again a former disused siding here still buried in the dirt.

One of the daftest ideas I heard from some railfans not long after the quakes was that the Waiau Branch would need to be reopened to Waiau because the present MNL route was likely to be abandoned and the railway constructed through the same inland route as what used to be Highway 70 to Kaikoura. This was never going to happen because SH1 runs alongside the MNL for much of the way and the reconstruction costs would be shared in many places. And the inland route north of Waiau would be very expensive to construct. For the Waiau Branch the Weka Pass section was the most expensive form of construction with the many cuttings and embankments, then the country from there to Waiau was pretty easy but then north of Waiau it is all very hilly and would be very expensive to build. History is clear that the Waiau Branch was one of the routes that was considered to take the MNL north but like all the other ideas (including the Mendip Hills section) it was ultimately obsoleted in favour of the present route. The line to Parnassus which finished in 1912 was actually built as the Cheviot Branch. But obviously by that time it had been decided to make it the main line north because, probably, the inland route north of Waiau was going to have too many problems. So there was never ever going to be any likelihood the Waiau Branch would ever be re opened as the MNL in the future, it is well over 100 years since that decision was taken, as in reality, most of the damage south of Kaikoura is confined to a relatively small stretch of route between Claverley and Puketa.

Bridge 95 and Tunnel 1. There was a bit of damage at Bridge 95 that needed to be repaired, I don't recall the details right now.

Bridge 96 is the famous Okarahia Viaduct. The machinery at the south end was already there before the quakes and was removing the side of a cutting that has given a lot of trouble from slipping. There has been no information suggesting any problems with the viaduct itself; it was probably designed to withstand quakes as this became a focus in the 1940s and the bridge at Kopuawhara on the Gisborne Line, which has similar piers but also has an arch that is not present at Okarahia, was also designed with quake resistance in view.