My comment about imperfect aerial imagery is further reinforced by the pictures of Slovens Creek viaduct that is twisted like there was a big earthquake at its base, lol. This is one of the issues which can happen with aerial photography when the ground height modelling that they use miss an object that is above the ground like the viaduct. The software that is used to correct perspective distortions that occur in raised terrain (including buildings and hills) actually creates distortion of above ground objects it doesn't know exist.
After looking at available aerial photos from Rolleston all the way through to Kotuku I am adding a number of small stations like Avoca, Cass, Cora Lynn, and I am looking at Aickens, Jacksons, Inchbonnie, Kotuku, Moana, Poerua, Rotomanu, Ruru and Te Kinga and also some locations in Canterbury but I will not make any guarantees which stations in the latter list will be mapped as most aerial photos available are from 1980s when many stations were semi closed or maybe only had a passenger platform. Beyond Arthurs Pass these are the only aerial images available at present on Retrolens. There is however 1940s coverage at a few locations in Canterbury that I may yet bring in.