Early European settlers drove sheep around the shoreline rather than attempt to cross the Rimutaka Range between Wellington and Wairarapa. When a railway was built over the mountains in the 1870s, the steep gradient on the Wairarapa side required Fell engines, which have extra horizontal wheels on a central rail. Fell engines were used on the line until a 9-kilometre tunnel opened in 1955. Archival audio sourced from Radio New Zealand Sound Archives, http://www.soundarchives.co.nz/. Sound files may not be reused without permission from Radio New Zealand Sound Archives (Reference number sa-t-0229pm).