This is basically the “Dunedin Suburban Area”, which is the extent of coverage of suburban passenger transport in the Dunedin area. This is a three part article incorporating 33 maps which were originally produced at 1:2000 scale. N.B. Due to some vagaries of Blogger the maps get resized to a smaller scale so I can’t really help by saying what the actual scale is that you will see in the maps following.
Just north/east of Dunedin there is this interesting deviation that involved a station called Pelichet Bay (see the third map, below).
Because of the construction of Forsyth Barr Stadium at Awatea St, the powers that be decided they wanted to push State Highway 88 through on a new route alongside the main line. This involved ripping up a number of railway sidings so that part of the rail corridor could be stolen for the highway.
Here we can see the site of Pelichet Bay station at the corner of Frederick St and Anzac Ave (approximate location). There in fact was a bay there at the time the railway was originally built; the line was deviated onto a causeway in the 1920s, unlike the other bays north of Dunedin this one was completely filled in, in fact the land on both sides was reclaimed so the shoreline has moved out a lot.
The doubling project of 1908-1914 between Dunedin and Mosgiel involved a lot of work to improve the gradients and eliminate level crossings. The work more or less starts about where the Dunedin Loco sidings come off at the left; the main line was raised up on an embankment at 1 in 100 to take it over Andersons Bay Road which was the first crossing removed. The dashed line to the right is approximately where the main line would have run originally. The DP & Ocean Beach Railway ended up going under the main line and the segment as far as Strathallan St is still in place today. The embankment was built up by constructing trestling, which was then buried, an old-school method of constructing embankments used around NZ before the advent of heavy earthmoving machinery.
The Andersons Bay Rd bridge still carries double tracks today but the extent of double track now reaches only a short distance to the south/west of this bridge. The original site of Kensington Station near King Edward Street, on the level, was replaced by a new station on the embankment at the north side of the new King Edward St bridge. The station had only pedestrian access, gained by a stairway entered through the bridge abutment rising between the twin tracks to the island platform. One side of the bridge was removed at the singling of the line and it has since been rebuilt with new abutments. A siding crossing Wilkie Road just south/west of King Edward Street bridge was probably removed when the line was raised, if not before. Just to the south/west is the current siding into the Hillside Engineering site. Wilkie Road Bridge has also been singled but retains its dual track abutments.
As the line came around the back of Carisbrook Stadium, this is about where the extent of the raising from Dunedin Station ended. My research found an old photo that shows there has always been a railway bridge over South Road. There have been not one, but in fact two, deviations of the line between Murrayfield St and Caversham Station. In 1910 the duplication work required a new double track replacement of the Caversham Tunnel at a lower level. A deviation was put in to take the railway line down to this lower level. This new section of double track remained in use until the 1980s. It was then that a proposal to build a new motorway through Caversham was put into effect. Up until that time the main traffic route was via South Road which was well clear of the tracks. In order to make room for the motorway a new single track railway embankment was constructed from Murrayfield St to Caversham so that the old route could be taken over by the motorway. This required a new railway bridge over South Road. The map above therefore properly shows this new section as always being single track. Due to the motorway construction, no trace can be found today of Caversham Station with its island platform, nor of the original 1874 railway route. The new railway route of the 1980s did bring one benefit and that was curve easing, the previous curve had a speed limit of 60 km/h, the realignment considerably eased what was quite a spectacular S bend at this location. The 1910 route on the other hand was first started in 1907, but was not finished until after the new tunnel had been built, due to a lot of unstable ground in the area causing many problems with the construction.
Continuing south/west from Caversham we can see how the railway and the motorway bisected Caversham. There were six north/south aligned streets that all got bridges to replace level crossings when the new line was opened in 1910. The advent of the motorway resulted in all of the streets except Barnes Drive being closed, and given new names on the true north side. The bridges were all removed except at Barnes Drive, and at Goodall Street (between Catherine Street and Asquith Street) where it is still used for access to a footbridge over the motorway. Before there was a motorway, South Road came along to Caversham Place and crossed over the railway line on a massive bridge that is still in place today, although now on a dead end. Just south/west of this bridge the present day Caversham Tunnel is encountered. This is constructed through sandstone and is completely unlined except at the portals. This is a very wet tunnel and at the time of completion was discharging more than 60,000 litres of water a day, which was piped to Hillside.
Continuing to the south/west are the two Caversham tunnels. The portal of the original is now below the motorway which at the time of the recent reconstruction (2009-10) was carried directly over the top of it, when formerly it was to the side of it. The tunnel remains accessible and has in recent years been used by the DCC Waterworks department to carry water and sewerage reticulation. The approach to the north/east portal is made through a deep sandstone cutting and there used to be a footbridge over the top at the end of Lindsay Road (off Rockyside Terrace) but this was removed in the recent motorway works.
The original tunnel came out below Kaikorai Valley Road which crossed over the top of it. Since closure of the 1874 route the overbridge was removed, but a culvert was put underneath the road to carry waterworks pipes. The railway bridge over a stream just to the south/west of the road is gone but a road bridge was built parallel to it to give access into the old fertiliser works site. Sidings shown on the map at the old Cattleyards station are those which existed in about 1964, all of the industries at the site now being closed. The current Caversham tunnel exits into a cutting just to the north/east of Kaikorai Valley Road. The line then passes through the former site of Burnside station.