I had the pleasure of working with a railroad fan (not into modeling just yet) from New Zealand. He showed me the Raurimu Spiral on the web. Makes me want to fly down there to ride around it (among other things).
It would be a very cool and interesting thing to model, only New Zealand Railways isn’t that popular and I’ve already commited myself to a layout. Good Luck to anyone who does!
If you go S scale, modeling New Zealand is no problem. Some the finest Kits i’ve purchased are those produced by New Zealand firms of local prototypes, other S manfactures could learn from them.