The Severn & Wye Railway was authorised by an Act of Parliament in 1809 and opened the following year as a horse-drawn tramway. In 1865, five locomotives were bought and the route was largely converted to broad gauge in 1868-9. Standard gauge arrived in 1872.
That year, a Mineral Loop was added to avoid the need for reversing movements at Cinderford.
The tunnel was requisitioned as an ammunition store between April 1942 and December 1943 before completely closing to traffic on 13th March 1951. In the Seventies, a short section of the tunnel near its centre was strengthened with rail and timber bracing to help it withstand the forces from traffic passing on the road above. This has though been recently fire-damaged so its effectiveness might have been somewhat compromised