Carnon viaduct

[1] The present nine-arch masonry viaduct replaced an earlier 19th-century structure designed by Isambard Kingdom Brunel for the Cornwall Railway.

It was built by A E Farr CIvil Engineers of Westbury for the Great Western Railway[3] as an entirely new structure immediately south of its predecessor and it cost £40,000.

"[2] After exploratory drillings, the engineering contractors sunk cast iron caissons through the silt to the bedrock at each pier location.

The cylindrical caissons, 16 feet (4.9 m) in diameter, were then emptied of silt so that masonry footings could be built from the rock up to surface level, pumps being employed to keep the workings dry.

This added to the cost of construction but proved entirely satisfactory as Carnon was among the last of the original Cornwall railway viaducts to be replaced.