Tramway Trickery was amongst the first caches this CO recorded a DNF on - it certainly did live up to its name. It is fitting to both resurrect the link to this venerable old GZ and to reinvite cachers to one of those spots one might not come across if it weren't for caching.
Rather than recreate or summarise some very good resources that are already out there here is a summary with some links to sites for further reading.
The Roslyn cable car line was Dunedin's first, beginning service on Feb 6, 1881 initially only going as far as the town belt. Eventually the line extended from Rattray Street, cutting through the town belt in Bellknowes, past the Beverly-Begg observatory, up the full length of Ross Street into Belgrave Crescent, through the cutting at GZ and then down to the valley near Frasers Road. This line included the world's first pull curve - a design feature necessary to combat Dunedin's steep streets. The service ended on Oct 26, 1951. The restored Roslyn No.1 tram will be displayed in the Otago Settlers Museum when it is expected to reopen in November 2012.
Expect a good deal of signal reflection / shadowing at GZ.
Links
Map of Dunedin cable car network
Cable Car Museum article on Dunedin's cable cars.
Photos of restoration of Roslyn No.1 tram.
Where are they now? Register of NZ's trams and cable cars.
Restoration of Roslyn No.1