About Old Coach Road
Exploring Today
The Local Area
Hapuawhenua Viaduct
The old Hapuawhenua Viaduct was classified as a Category 1 structure by Historic Places Trust in October 1995.
This viaduct is still an icon of the North Island Main Trunk railway.
The viaduct became redundant when a new concrete railway viaduct was completed in 1987.
From the top of the lower section of the Ohakune Coach Road at the old gate post, a new walking track was built to the tunnel portal and over the hill to the two Hapuawhenua Viaducts.
From Ohakune, the railway line has to climb around 500ft up to Horopito.
The railway tracks climb on a 1:50 grade for most of the way, a steep climb for steam locomotives.
A viaduct was needed to cross the Hapuawhenua valley.
Peter Seton Hay designed a curved steel lattice viaduct with 13 concrete piers and four steel towers on concrete foundations. Fred Furkett was the engineer in charge its construction.
Hapuawhenua Viaduct Workers Camp
The viaduct is 284 meters long, 45 meters above the stream and built on a 10 chain radius curve with a level deck.
Building materials were brought to the site from the present Ohakune railway yard, along a temporary tramway below the planned permanent level, which needed time consuming earthworks and fill.
By building the tramway to carry materials and supplies, the tunnel, the Hapuawhenua Viaduct and the permanent way could all be worked on at the same time.
A short branch line off this Hapuawhenua tramway led to the Ohakune station in the bush, where passengers left the train and boarded coaches to cross the Gap.
In the Hapuawhenua Valley below the viaduct, there is no flat ground, so before construction could begin, a 200 foot by 50 foot platform was built over the stream.
The cement shed, the mixer and its engine, a tool shed and space for storing steel work, were all placed on this platform.
The steel components for the viaduct were made at Mangaonoho, north of Taihape, then railed to Ohakune.
The steel work was assembled at ground level on site, and the towers erected on concrete foundations. The steel girders were then hauled up by derrick poles fitted on top of the steel towers.
Viaduct Before Restoration
A flying fox system for carrying materials along the length of the viaduct could not be used as this viaduct was curved.
It is surprising to learn that scaffolding was not used. The builders used ladders reaching from the foundations to deck level, about 45 meters above the stream.
Construction was completed with no serious injuries.
During the 9 weeks following August 9th, 1907, there were only 5 days without rain. Working conditions were not pleasant, especially during the cold freezing winter.
The old Hapuawhenua Viaduct was used by railways from 1908 till 1987.
The new replacement concrete viaduct was opened on May 2nd 1987.
A J Hackett ran New Zealand's first bungy jump off the old Hapuawhenua Viaduct in 1987.
Tongariro Natural History Society and Department of Conservation, with financial support from the Stout Trust, have cleaned the steel work and restored the decking on the viaduct.
Restored Hapuawhenua Viaduct
Now it is an exciting and safe experience to walk along the deck, study the construction and design of the viaduct, marvel at the new concrete viaduct and enjoy the serenity of the bush and the antics of the native birds.
Re-opening Day February 14th 2009
