Friday 13 March 2020

Wairarapa Line [0P]: Volume 6 Progress Update 16

Since our last update we have completed drawing maps of the entire Gracefield Branch and Hutt Workshops sidings. In the process of this we added additional generations of historical aerial mosaics both for the Workshops and for Gracefield, which added about a day. These mean that for Hutt Park (the workshops) we have 1939, 1969, 1978, 1986 and 1995 as well as present, whilst for Gracefield, we have 1939, 1954, 1969, 1981 and 1995. This is however strongly expected to be the full extent of any additional aerial photography needed from Petone to Haywards and as there are expected to be no additional changes observed historically in these areas that aren't covered by the aerial photography we already have, we expect to rapidly proceed with mapping along this section.

What will then slow things down is the section from Haywards to Upper Hutt. In the main, this will be due to the addition of further aerial coverage around Silverstream, which covers the changes in the area due to the deviation being built and the establishment of the Silver Stream Railway (SSR) as a heritage railway in the 1980s, it also documents the route the line took across the old Silverstream Bridge until 1954 as there is no trace of this bridge today. The deviation of the line meant the Silverstream station on the WL was moved so it is useful to be able to illustrate where the old station was.

As we head on up from Silverstream to Upper Hutt we will take in the Trentham Army Base and we will have to see if we have good coverage of this area with the existing mosaics that have been done from 1969 or 1970 otherwise we will have to add some more old stuff to the area but this should not be difficult. What we don't have for this area compared to further back down the line is good quality coverage from the 1930s/1940s. However we expect few changes would have taken place along the route apart from Silverstream, which we have covered separately, and Trentham, with its sidings. This is because the population north of Silverstream historically was relatively sparse pre-WW2 and only really took off in the 1950s like the rest of the Hutt Valley, which is what drove the expansion of the Hutt Valley Railway through Lower Hutt. When it was originally put through to Waterloo it was as much for industry as for the small amount of residential development at that time - a siding was put in at Ava for General Motors and further sidings at Waterloo which was the terminus. North of Waterloo was practically all still rural at that time and the extension was largely driven by the development of new subdivisions and projected demand growth.

The schedule is still well behind where we had hoped to be as we have passed the original deadline a few days ago for the entire volume and there is still a lot to do. We expect to be completed to Haywards by the end of this week and probably it will then take another week to finish the line through to Upper Hutt. We then have work to do on the Upper Hutt to Featherston section and Featherston all the way through to Woodville. We won't be adding any more aerial mosaics than we have already planned beyond Featherston - just that town, Carterton and Masterton. It would take at least another week to get through this and possible more, so there is at least two more weeks of work. 

We therefore have set our new deadline to be March 31st for Volume 6 and will be making every effort to keep to this as much as possible. Although progress has been slow this week we have successfully resisted the temptation to spend time fixing up misaligned aerial mosaics and there is just one fix to one area where adding a second image for the same area significantly improved the quality of the aerial map that will be produced. Aerial mosaic misalignments are quite a common reality when dealing with the challenges in putting them together out of multiple source images and we vastly prefer our changes to the map formats to display more information on a diagram map and less on an aerial map as the solution to misalignments, rather than trying to fix them as we have spent a lot of extra time doing in the past. This helps to speed up the overall process since the mosaic production is quite slow.

The entire Gracefield Branch, with Hutt Shops at upper left and Seaview at lower right. As always, this diagram is a composite view showing everything in one diagram, and it will be necessary to refer to the individual aerial views to discover the extent of track installations at a particular point in time.


Gracefield using 1969 aerial background. We are not going to label the individual sidings as this requires more research that we do not have time to undertake.

Hutt Workshops with the historical footprint of the site indicated by track locations that are now occupied by private industry or housing.