The 7-kilometre Mangaweka deviation, opened in 1981, is the most substantial realignment of the North Island main trunk railway since the line was completed in 1908. The new route moved the line away from unstable land, requiring the construction of three massive viaducts, which are among the highest in New Zealand, and are unique in their close proximity to each other. The earlier Mangaweka viaduct was dismantled when the deviation was opened, but the Makōhine viaduct, just south of Ōhingaiti, is still in use.