We're told about the Nihotupu Dam and how much longer than expected it took to build. It experienced its fair share of hold-ups, including its main contractor William Langlands being killed in a freak accident during blasting for the tramline when a flying rock hit him from 100m away.
Heavy rain and flooding further hindered the progress, and World War I didn't help, causing a major shortage of men and materials. From the time tenders were called in 1915 to completion in 1923, it was a difficult birth.
Today, though, the dam stands proud and, when we reach the top, find it is the backdrop to many photographs by the train passengers. We take our pictures and head back to the carpark, although this time, instead of running after our children, we're carrying them on our backs with red noses from the cold - it's the perfect Sunday walk to tire out the kids and let the parents get some exercise, too.
TRAVELLER'S TIPS
Upper Nihotupu Walk:
* From Scenic Drive head on to Piha Rd and park at the first carpark you come to. The walk is 2.6km long and takes about 45 minutes.
* Stop at Elevation Cafe for Italian pizzas, a glass of wine or a hot chocolate. 473 Scenic Drive.
* To book on Watercare's Rainforest Express ph (09) 302 8028. See the website for a schedule of trips.
Bookings office closed on weekends so plan your trip in advance, fares from $12 a child and $25 an adult.