Tokomaru Steam Museum is a museum at 742 Makerua Rd, Tokomaru, Horowhenua, rated 4.3 from 8 Google reviews. Its website describes it as a collection of steam engines that Colin Stephenson gathered from around New Zealand.
The website says most of the collection is under cover and regularly steamed, so visitors can see engines working rather than standing idle. Various locomotives and a Fowler traction engine are shown in steam at various times, and a large Corliss engine is among the collection. The collection was built to save fine machinery from being lost, which gives the visit a strong sense of preservation as well as display. Because engines are steamed at different times, it helps to check ahead for a day when the engine you want to see is running.
For a look at working steam engines just south of Palmerston North, Tokomaru Steam Museum is worth the trip.