Napier - Gisborne Railway
Engineering Work (eg road, bridge, sawmill, dam)
This line was a major feat of engineering, built through very difficult terrain and generally weak tertiary geological conditions. It was built intermittently from 1911-42 over 191 kilometres of hilly country with gorges requiring five steel viaducts more than 60 metres (m) high; a reinforced concrete arch viaduct, other bridges, numerous tunnels and heavy earthworks.
The steel viaducts include:
- Waikoau, north of Napier, 72 m high, completed 1928
- Matahourua, 65.5 m high, completed 1929
- Waikare, 79 m high, completed 1929
- Mohaka Viaduct, 95 m high, completed 1937
- Mangaturanga, 65 m high, completed 1938.
The Wairoa River Railway Bridge built in 1930 has steel through trusses. At Napier the Westshore bridge completed in 1918 has nine steel plate girders and a reinforced concrete bowstring arch over the main waterway. Built for road traffic provision was made for the 4.26 m rail track to be laid alongside later. A little further north is the Esk River Bridge completed in 1925 having nine steel plate girder spans.
The railway from Napier to Waikokopu was in the Napier Public Works Department (PWD) District under Alexander Dinnie. Waikokopu to Gisborne was in the Gisborne PWD District under Onslow Garth Thornton.
Near Waikokopu the Waiau Stream Viaduct completed in 1942 has a reinforced concrete parabolic arch with eight reinforced concrete girder spans and is 30.5 m high. Designed to resist seismic forces it was 'state of the 'art' being both majestic and attractive.
The south portal of the Tikiwhata Tunnel is at the north end of the viaduct. It is the longest of all the tunnels on this line being 2988 m long. The next longest is the Waikoura Tunnel, 1448m long. There are 16 other lesser tunnels on this section. Of the 16 bridges the longest is the Waipoua River bridge with 15 steel plate girder spans.
There were many delays, the 1931 Hawkes Bay earthquake causing some damage to several viaducts and bridges, as did the two disastrous floods of early 1938 with loss of 22 lives at Kopuawhara. During the Depression all construction ceased for several years.
Related IPENZ record:
Kopuawhara Railway Viaduct
Notes by G G Thornton, April 2010
Geoffrey Thornton, Bridging the Gap: Early bridges in New Zealand, 1830-1939, Reed, Auckland, 2001
Rosslyn J Noonan; By Design: A brief history of the Public Works Department and Ministry of Works, 1870-1970, Ministry of Works and Development, Wellington, 1975
Between Napier and Gisborne
East Coast, Hawkes Bay
The railway is at times close to State Highway 2 (SH 2). There is a good view of the Mohaka Viaduct from SH 2
Nature of Engineering
(Click image to enlarge )