The Clarence Railway Tunnel is part of the Zig- Zag railway system near Lithgow in New South Wales. This is one of the tunnels that was allegedly storing chemical weapons for a long period after WW2. The photographs below were taken after the tunnel was cleared and as works were being undertaken to re-lay the railway tracks.

This railway is now operational again and is a popular tourist destination to travel on the steam locomotives that are used. The tunnel is adjacent to the Bells Line of Road, about half a kilometre west of the Clarence Railway Station. There is a walking trail that passes the tunnel to the north, and a viewing area beside the road. The tunnel is a very short drive from the Lithgow anti-aircraft battery site. This is now an active railway, do not enter the tunnel without consulting the railway operator.