Victoria Tunnel, Queensland

The Victoria Tunnel is a railway tunnel located in Queensland, Australia. At 537 m, the tunnel is the longer of the two oldest railway tunnels in Queensland, the other being known as the 'Six Chain', either because it is 6 chain long, or is situated entirely on a 6 chain radius curve, or both. Both are situated on the Main Line from Brisbane to Toowoomba, being part of the first narrow gauge main line in the world.

The Victoria Tunnel was named in honour of Queen Victoria, the reigning Australian monarch at the time of the tunnel's construction.

History
The 537 m tunnel (together with 'Six Chain') was built through the Little Liverpool Range on a section of narrow gauge railway from Grandchester to Gatton. The railway opened in June 1866, being delayed when the excavation of the tunnel revealed unexpected geological difficulties, requiring the tunnel to be lined with 3 layers of bricks. That resulted in the tunnel having restricted clearances, which limits the loading gauge (size of rolling stock) on this section of the Queensland Railways network, and the floor of the tunnel was lowered by 150 mm in 1985 to improve that situation.

Tunnel floor lowering
There are a total of 11 single track tunnels on the line between Ipswich and Toowoomba, all built around the same time in 1865, all with a tight profile that are too small to take 2.9 m ISO shipping containers. It is now proposed to improve the loading gauge of these tunnels by lowering the floors.