The largest bridge on the Napier-Gisborne Line is Bridge 290, which crosses the Waipaoa River between Matawhero and Muriwai. It encloses the 380 km peg which is about 1/3 of the way across the bridge when heading northwards, and is therefore 380 km from Palmerston North, 200 km from Napier and 10 km from Gisborne. The Waipaoa River bridge was built in the late 1930s and had an original length of 220 metres in 15 through-plate girder spans. The three photos below are from Auckland City Libraries. (Sir George Grey Special Collections).
This photo is from Gisborne Photo News and was published in 1956 showing a large flood passing beneath the bridge.
A few years after the line opened, in 1948, there was a very large flood in the Gisborne district, which had an estimated peak flow volume in the Waipaoa River of 3960 cumecs (which is about 4 million litres of water per second) and as a consequence, flood protection works were constructed, with the result that the bridge was lengthened by 110 metres at the south end. This entailed rearranging some of the existing spans and adding three through girder spans; the entire bridge was also raised by about 0.6 - 0.7 metres. These works were carried out between 1956 and 1958. The 380 km peg is immediately to the south of these new spans. Part of the construction works required a deviation to be made at the south end of the bridge to keep the line open.
The next two photos showing the work being started on the bridge were published in Gisborne Photo News in November 1956.
The next three photos were published in Gisborne Photo News in May 1957.
It is hard to believe today that the bridge was originally as short as seen here: less than half its present length.
The next photo is from Gisborne Photo News published March 1958.
The second part of this article will have more photos of the 1958 deviation being completed and also describe the 1988 extension of the bridge.