Thanks for the trip down memory lane. I used to live in Mangapai, right by the bridge and could watch the trains come up from the coast. The line North of Kauri and the branch to Dargaville were still operating, sort of, with ancient 2-axle open wagons loaded with logs. At the Portland siding there were 2 small shunters parked, owned by "Forest Loaders". All history now. When you see the trains crawling along, the steel screaming in the tight bends, you start to understand why none of this can ever be economical. It takes the Swiss to properly run a metre-gauge rail network, in the Alps and making a profit.
There is no comparison between Swiss metre gauge and NZ trains. Our population is a bit over 5 million. Switzerland is roughly in the middle of Europe which has a population of just over 741 million. A lot of tourists to pull in to use the trains. Getting NZer’s out of their cars even where there is a good public transport is nearly impossible. And KiwiRail don’t exactly help when new customers come along, often they just don’t have the capacity as there has been a lack of investment over many, many decades.