Wairarapa Line [0N]: Volume 6 Progress Update 14

Work has proceeded on he Volume 6 maps more slowly this week than in most previous weeks and although major yards like Petone aren’t too common in the Wellington suburban area, with the work on other segments further up the corridor, we are now estimating about another two weeks to complete this volume so it will be closer to the end of March to have it finished. As with always, we do have the advantage of being able to build on previous work done and not having to put everything together from scratch, but there is still a lot of detail to fill in. As it has become clear that we simply will not have time to do our in depth articles that we have done in the past for various stations, these updates will continue to include some maps of the areas we are covering with a few sentences of information about each place. We are not confident of resuming the indepth articles when the volumes are complete so this is really where we have got to with our historical posts about various stations and lines.

Whilst we do have the 1938 or 1939 aerial photos of the Lower Hutt area that were done at between 1:6000 and 1:10000 scale and will cover much of the current segment of Petone to Waterloo and Woburn to Seaview, a lot of what was taken up the western side is in deep shadow (it does seem strange that they chose to take the aerial photos late in the day) and is consequently hard to pick out so we have had to limit the amount of work we can do with this but it has been possible to fill in the old double track from Petone to Lower Hutt which was removed in the late 1950s. This includes drawing in what used to be called Hutt Valley Junction and is now known as Melling Branch Junction. 
Referring to S&I Diagram No. 665 of Petone in 1952, the lines to Lower Hutt were at that time shown as Down Main and Up Main with the Hutt Valley lines shown as Down Branch and Up Branch. The Lower Hutt lines continued more or less straight while the Hutt Valley lines curved away. These days that curve is still there but the Melling Branch also curves a bit more because of junction realignment and singling.
The map below of the junction uses the 1939
aerial photo background which is the best aligned part of the coverage
from Petone to Melling as every other part is misaligned. However we
will not be correcting issues like these in aerial maps as we do not now
show the full track detail or in fact much detail at all on aerial maps
in order to be able to work with misaligned backgrounds without too
much visual conflict. The other main reason being to allow the aerials
to be viewed without their interesting detail being obscured too much by
map information. This map is not a production map, it is a design map
created just for this blog, as will be commonly seen in these blog
This doesn’t mean we don’t make every reasonable effort to try to line everything up for the maps between different generations of aerial photography but it does signal that often many of these alignment issues are extremely difficult to avoid or overcome for various reasons including limitations of the computer software we use to produce the historical mosaics, and straight out technical challenges when trying to match up old aerial photos to modern day ones because of various reasons including older photographical technology with greater limitations than exist today, and the fact that the historical imagery may either not be ortho-rectified at all, or any orthorectification that was performed was significantly different from the current. At the moment we are assuming none of the historical aerials we have obtained have any orthorectification and therefore will contain a lot of perspective distortion in various places.
So here’s Hutt Valley Junction using 1939 aerial photo background. Coming in from the left is the present junction onto the current Wairarapa Line Up Main to Trentham where it currently ends (but the double track is currently being extended to Upper Hutt). The junction is now called Melling Branch Junction just past 11 km. Although 11.02 km as recorded in the Working Timetable we use for reference appears to be incorrect. Just a little past that is the junction used for what was the Hutt Valley Branch begun in the 1920s (the first section to Waterloo officially opened in 1927). This branch became the main line in March 1954 and the western line was cut to Melling and became the Melling Branch at the same time. Just past that junction was a small bridge which all four tracks crossed, which has since been filled in. We can see that the current route of the Melling Branch single track, whilst coming off the Up Main and following its route for a short distance, does in fact cross over to the old Down Main route just past this bridge, so that the former Up Main from the original junction actually crosses over the present line.
To help illustrate the magnitude of these changes, here is the same view superimposed on 2017 aerial photography except with most of the overlays turned off to make it easier to view things actually on the ground.
The western line was originally doubled in 1905 only as far as Lower Hutt. The 1939 and other aerial photos we can reference suggest that Lower Hutt never had more than a single platform and probably the doubling was because there was significant passenger and freight volume from Lower Hutt but at the time there was virtually no population further north. These days there are places like Tirohanga and Kelson where subdivisions have been carved out on the hills above the western side of the Hutt Valley, and a greater amount of residential development on the flat in the Andrews area, but in the era up to the closing of the western line beyond Melling, the route at that point was very rural. Even after crossing over to the eastern side of the line at Silverstream and carrying on north to Upper Hutt, population in those areas in the earlier days of the railway was a lot less than currently, as much of the Hutt Valley was undeveloped for residential purposes. The Hutt Valley Branch through initially to Waterloo, and subsequently up to Haywards where it joined onto the existing western line and subsequently supplanted it, was built as part of new residential development of the Hutt Valley sponsored by the Government of the day and it also connected to the new railway workshops at Woburn and facilitated significant industrial development in these areas as well. We shall explore this more in subsequent updates as we continue with our progress in map production.