Friday 28 February 2020

Wairarapa Line [0J]: Volume 6 Progress Update 10

Since our last update we've made a lot of progress on all the mosaics which are in six separate projects. We have extracted tiles so far for Wellington to Ngauranga. Whilst that doesn't sound like a lot, the mosaics for the other areas have practically all been completed except for Featherston-Masterton and the Greytown Branch (all in one project) and those tiles are being extracted over the next couple of days. So the time schedule is going quite well and we are focussing on completing historical tiles rather than drawing maps. The tiles are going into the GIS as soon as they are extracted to be checked for any issues which are then being resolved as needed.

The significant works done in the last few days are particularly in the following:
  • Petone to Waterloo and the Gracefield Branch where we have added 1938 historical content, particularly around Petone-Melling and Seaview. There were some surveys done in 1938 which are at scales varying from 1:6000 to 1:10000 which is quite high for that era - most of what we can get for the period around the country tends to be around 1:16000. So that enables good quality maps for the era.
  • Waterloo to Haywards where larger scale 1938 surveys again were used to get all the way up the western route to Belmont Quarry (the last station before Haywards) and on the current route to Taita. Smaller scale coverage completes what is needed for this set of maps so that both routes are completely covered.
  • Haywards to Upper Hutt where some 1963 coverage was found for the Upper Hutt station.
  • Upper Hutt to Featherston where 1941 coverage of Summit and Cross Creek was added to the existing maps which as we mentioned in a previous post we didn't have coverage of previously while the line was open. With other bits and pieces we now have better coverage of the original route over the Rimutakas quite well, including Maymorn during the deviation construction era when it was the work camp site. 
  • We haven't got around to enquiring about the 1951 survey of the Hutt Valley and Rimutakas that is currently unavailable in Retrolens, but have been able to use some historic maps that we were able to download from another source. Also there is some 1957 coverage of parts of the area such as Maymorn which was still very much like the construction era in appearance, and Speedys Crossing near Featherston. 

Maymorn and Speedys Crossing were the two places where connections between old and new routes were maintained for construction access during the deviation contract and remained as such for several years afterwards until the original line was completely dismantled. Having two connections was necessary because the centre rail of the Rimutaka Incline and the old small section tunnels imposed loading gauge restrictions for modern rolling stock. Most of the actual construction supplies and equipment needing to be sent by rail during deviation construction was sent from Wellington through the connection at Maymorn. After the deviation was opened, with the much greater ease of access to Featherston, the connection at Speedys Crossing was used more. Both connections are shown on 1955 and 1957 S&I diagrams, the one at Speedys Crossing came off the main line with its own switchlock and at the time the diagram

So these areas are practically complete and extraction is being prioritised along with the completion of the Featherston-Masterton / Greytown project and resolving any issues that have been discovered when tiles are extracted from the mosaic projects.

The base aerial coverage for Featherston to Masterton is only available in 0.3 metre resolution and has been scaled to 0.15 m in the mosaic projects to be a better match for the high resolution NZR station surveys of the three stations concerned. As usual, Qgis will be instructed to draw the extracted tiles at 0.15  ensuring that we are able to make use of the full resolution of the historical tiles.

At the time of writing we have spent a couple of days fixing issues with historical content for Wellington Yard. This is some indication of the type of problems that we often don't discover until we are looking at the tiles in the GIS. However that same period of time has also been spent on extracting tiles from the other projects all the way up to Waterloo, so actual presentation of completed tiles to the GIS is more advanced than just at the Wellington end of the line. It is, however, quite possible that the tiles may not be fully completed for another three or four days, depending on how many other issues are found, but we hope in reality that we will have all of them in use ready for the start of next week. However there is so much extraction work, checking, and finishing the one remaining project that has not yet been completed to do, that it is quite likely we may not have actual maps starting to come out for another 4-5 days and that it could well be the case that the publication deadline for Volume 6 ends up being somewhere around the 10th of March, or exactly a month after Volume 2, and leaving us in actuality unable to make up any time at all on our overall schedule.