Friday 12 January 2018

MSL Dunedin (2J): Updating / Blanket Bay

As you can see I haven't actually put anything out about the station yard. That's because I have got hold of some 1947 aerial photos that will probably be the best ones to see if I can use them for the station yard, if they are sharp enough.

Anyway let's look at something else. Blanket Bay is the next bay south of Sawyers Bay, and the coast-hugging route of the original Dunedin-Port Chalmers Railway went through a tunnel of 101 metres length. As the current tunnel aligned to the causeway is at a length of 313 metres, the single track bore is much shorter.

Every man and his dog has been to Sawyers Bay to try to locate the old tunnel. After all, the Quail Atlas shows the north portal should be right alongside the same end of the current tunnel? Unfortunately, this is one of the many mistakes in the Quail Atlas. As it happens, the south portals are close together (along the railway axis) and this puts the old tunnel in quite a different location relative to the present; about 200 metres further south. So the idea that you are going to find anything in that cutting next to the north portal of the double track tunnel, is regrettably mistaken.

All the below photos use 1947 aerial photography overlaid over current Linz 2013 aerials.

The tunnel basically went under the old road at this point. The highway, which was completely new, cut through the hill where this road crossed over. 


These two views give a fuller picture of the old railway cuttings and how they have been covered over by highway construction. I think it is quite safe to conclude the highway goes almost all the way over the top of the old railway cuttings and tunnel.

The position of the tunnel is corroborated by this NZMS1 map from the early 1940s.