Friday, 31 March 2017

Otago Central Railway [14]: Finalising the Cromwell Gorge

So I have been taking a look at the Cromwell Gorge aerial data again after discovering my maps didn't line up with the 0.4 metre aerial photos from LINZ. Well it turns out that I completely misaligned the aerials when I originally checked them against the original maps. In fact it was done very quickly and roughly, enough to create more than a few errors.

Qgis does a great job with georeferenced images of loading them in the right place. However with images that are not georeferenced you have to use a built in wizard. It would make more sense to me to be using a transparency overlay to map the points directly, and that's because their wizard couldn't make things line up when I tried it twice.

The very first attempt to get things in line properly has put most of the Cromwell yard under dirt at the toe of the highway, rather than in the water. For years people have speculated about the supposed underwater finds to be had. Whilst some may exist, the statement by D&E that no traces remain west of Clyde is probably closer to the truth of the matter. The fact they have stated for example that the Leaning Rock bridge was buried under a pile of rock prior to filling the lake, and that bridge being built of concrete was one of the very few that were not actually removed outright. The aerial photo set from 1992 shows really very little trace of the railway by that stage as a lot of earthworks had occurred. 

My new understanding of where the line ran due to adjusting the position of the aerial photos puts a lot more of it onto dry land, but not where it can be traced as a lot of this has been contoured by machinery destroying any formation traces. Even in places where a formation can be discerned like at Brewery Creek near Cromwell or Gibraltar Rock where the original rock cutting is still well above the water line, people who have had a look report there are no traces of anything of a railway nature to be found today.

It shouldn't take long to get the images realigned and then the proper lineup put in for the actual road, railway and other features going through the Gorge. Finishing the maps is all important because then I can start writing my article.

Monday, 27 March 2017

Otago Central Railway [13]: Locating the new Clyde station

One thing I don't have at the moment is a source document showing exactly where Clyde was moved to in 1980. We know where the railway yard was, but not where the location of 214.38 km was exactly, which is the kilometrage shown in various sources for the new station, because there isn't a new chainage chart for Clyde. (I don't know what was used after the lines were metricated to replace the old chainage charts)

However we can convert the mileage to the metric equivalent by using, for example, the bridge list and converting this distance. The last bridge just before Clyde is the Muttontown Gully Viaduct (No.86) and from D&E, we know that the east abutment is at the metric location of 213.31 km. So I can do my measurements from that location which on the chainage chart is 132 miles 48 chains 5 links.

Basically using that and knowing also the fact that there was only a very small difference between the imperial and metric distances at this location, I came up with the 214.38 distance being the entrance to Clyde yard, rather than being where we would expect it to be, which might be alongside the goods shed or something. In other words that is where 1070 metres from the east abutment of Bridge 86 is.

Another way to reach this measurement is to go from the end of rails at 214.95 km and measure backwards. So by these measurements we get only an approximate location, that one shown below, as the measurements don't quite match up.

Sunday, 19 March 2017

Otago Central Railway [12]: Clyde overview

Here are some more maps of Clyde:

Here's a good overview of the Clyde area and showing how the line headed up into the Cromwell Gorge, compared to where the dam and Lake Dunstan are today. Bridge 86 seen out to the right is the Muttontown Gully viaduct.

One of the aerial photos I have (back when I was paying $50 a session to Archives New Zealand to scan 10 images at a time from their contact prints of the L&S collection) of Clyde is from a series I got of Clyde-Cromwell dated 1992. At that time the track lifting of the Otago Central Line was well under way and all of the Clyde yard should have been lifted along with all of the sidings that would be visible in this picture. You can see a lot of other changes from some of the earlier photos I have such as the Ministry of Works houses being removed etc. The Clyde yard today is changed a lot although the main railway structures are still standing. The function of the long thin building right above the railway yard is unclear; it was not there in 1981 and presumably did not have a railway function. It still stands today.
New Clyde had two "yards" in effect: there was the main freight and operational yards where the goods shed, engine shed and turntable were located at the westernmost end of the line. Then there were the sidings adjacent to the MOW depot which started at Young Lane and went west to a point where there was a short section of mainline between the two locations. Here are the sidings near the MOW site coming off the mainline at Young Lane.

This map shows more clearly the separation between the two yards. Note that for the main Clyde yard, I still have a bit of work to line things up from between the two sets of aerial photos I have, so the track layout seen to the far left is probably somewhat incorrect at this time. We can also see the MOW sidings into their own depot curving off in a northerly direction.

This is what that MOW depot and sidings looked like on the ground. Photo taken September 1989 by Patrick Dunford.

Overview of the MOW depot site. Compare with the aerial photo above.

Closeup of the MOW depot. Definitely worthwhile for someone to have a look closeup at the depot sometime. It isn't clear whether the buildings are new or parts of the old building; what is reasonably clear is that the entire footprint of the depot building that can be seen in the aerial photos isn't currently occupied; you can see concrete footings that are exposed.

I will have more of Clyde as soon as I get the main yard redrawn since as mentioned some adjustments are needed (as have been made in most of what is included in this post)

Thursday, 16 March 2017

Otago Central Railway [11]: Alexandra-Clyde

At the moment I am focusing just on getting the main line aligned from the aerial photos and haven't drawn any more station layouts or milepegs in since Wedderburn Station and MP112 (Omakau). However soon enough the alignment work will be completed right through to Cromwell as I have just reached the outskirts of Clyde. Here are some images.

Bridge 85, also known as Manuherikia No.3 Bridge, is a formerly combined bridge just east of Alexandra. The railway track, of course, originally went down the middle of the bridge, which is one lane for road traffic. The rail trail has been diverted onto a new footway clipped onto the side of the bridge.

Alexandra railway station. Although the station building was still extant at the time of line closure, it is one that did not survive, being demolished. There are relatively few places on the line where a station building still there at the time of the line closing doesn't exist any more. We have Ranfurly, Hyde, Pukerangi, Hindon and Clyde (both sites) station buildings still in place for example. The Kokonga and Ida Valley buildings are elsewhere in Otago/South Canterbury and the Wedderburn, Ngapuna and part of Galloway are among those which have been returned to the site as part of the rail trail, all these having been removed with pre-1990 yard closures.

Here you can see where the Alexandra station platform still exists.

A building at the corner of Dunstan Road and Chicago St, Alexandra, carries this mural of the old station with a Vulcan railcar and a steam train, and a wagon being loaded.

A little known fact is that the track deviation for the new Clyde yard began at Youngs Lane, rather than where the new route curved away towards the post-1980 terminus at Sunderland Street. This allowed 500 metres of the old rail corridor to be turned into the new Highway 8. The Clyde yard eastern limits were at the same location with the sidings coming off the main there. There was never a permanent level crossing of Highway 8 by the railway, although a temporary connection was made at Sunderland St between the old line to Cromwell and the new railway alignment.

Sunday, 5 March 2017

Otago Central Railway [10]: Omakau

Well I have been very busy over the last week or two and haven't done any maps much.

Here anyway is an aerial shot of Omakau with the platform and goods shed clearly visible. As mentioned last time I am just whizzing along and marking in mileposts etc and not drawing yards at the moment but I will get back into the layouts later on. Omakau had quite a big layout with the engine shed and triangle and quite a lot of other sidings and stuff.