The Lithgow Zig Zag is a tourist railway operating on the former NSWGR Zig Zag—known as a switchback in some locales—from Clarence to Lithgow. Due to increasing traffic the line was closed in 1910 and replaced by the 10 tunnels deviation. The right of way was accessible to vehicular and other traffic until 1975 when it was reopened as a tourist railway—albeit operating a 3'6" gauge system principally running Queensland rolling stock.
The Zig Zag has had a few issues recently, including a disastrous bush fire, but appears to be on the road to re-opening.