Certain tunnels are inadequately drained and suffer from deterioration in the tunnel lining, causing water leaks that necessitate reductions in speed.
This gravel contains oil and is therefore unsuitable for cementing the tunnel lining.
The water forced its way through the creek bed, around a portion of the tunnel lining and found an outlet through the weep-holes of the masonry work.
Some masonry work, including a portion of tunnel lining, can still be seen in a field near Bullo today.
George W. Jackson was granted a patent on the system of forms used in making the concrete tunnel lining.
The tunnel lining is the wall of the tunnel.
The heavy traffic took its toll on the tunnel lining.
In the 1930s, the firm designed the first bolted concrete tunnel linings, for the London Passenger Transport Board.
The tunnel linings will be constructed from concrete sections.
The mid-size one we call 'crackle,' because it seems to cause more fracturing of the tunnel lining.