The Ten Tunnels Deviation is a heritage-listed 9.2-kilometre (5.7 mi) section of the Main Western Line between Newnes Junction and Zig Zag stations in Lithgow, New South Wales, Australia. It was designed and built by the New South Wales Government Railways and built from 1 June 1908 and 16 October 1910. It is also known as Great Zig Zag Railway deviation tunnels and Bell to Zig Zag Ten Tunnel Railway Deviation. It was added to the New South Wales State Heritage Register on 2 April 1999.