Fabulous miniature train set up in Havelock North. The length of the ride is very decent, and there are lots of features like a viaduct, several bridges and tunnels to enjoy. There are multiple trains running at once, so when if it's busy you're not waiting too long for a ride... This is so important when you have toddlers.
The fares are very reasonable, especially given the amount of work that would have gone on to develop the railway in the first place. The whole thing is run by volunteers, which is impressive, but also I guess allows the fares to be as low as they are.
The only issue we had was nothing to do with the set up itself, but by selfish people who can't be bothered waiting their turn. That was a minority though, as most people there were well behaved, and very respectable.
We had a great time there, despite having to tell 2 toddlers it was time to go, and they couldn't ride the trains any more. Highly recommend coming here if you're a miniature train enthusiast, or if you have young kids, as you won't be disappointed.