Qualla: Cornwall Railway Viaducts

Cornwall Railway Viaducts: Introduction

Sat, 23 May 2026 00:00:00 GMT

Photo credit Great Western Railway, Public domain. The line had to cross 45 rivers and deep valleys in 70 miles. The money had run out. Isambard Kingdom Brunel sketched a solution: instead of stone arches all the way to the riverbed, plant compact masonry piers thirty-four feet below the rails and let fans of yellow-pine timber radiate from each one to support the deck. Cheaper to build, more expensive to maintain - he warned them about that explicitly, ten thousand pounds a year - and astonishingly graceful to look at. Forty-two wooden viaducts went up between Plymouth and Falmouth. The first opened in May 1859, with Brunel dying that September before seeing the full line in service, under the supervision of his lieutenant R. P. Brereton. The last of them stood until 1934. Today, all that remains of most are the stub piers, alone in the fields beside their stone successors, looking like the legs of some vast creature that walked across Cornwall and was never quite finished.

Image: Great Western Railway | Public domain

Cornwall Railway Viaducts: Five Designs for Five Valleys

Sat, 23 May 2026 00:00:00 GMT

Photo credit Geof Sheppard, CC BY-SA 3.0. Peter John Margary, the Cornwall Railway's engineer from 1868 to 1891, gave each design a letter. Class A, the workhorse, used three fans of timber struts spreading at angles of 55, 75, 105, and 125 degrees from horizontal off the top of each pier - the iconic backslash-slash for...

Image: Geof Sheppard | CC BY-SA 3.0

Cornwall Railway Viaducts: The Maintenance Problem

Sat, 23 May 2026 00:00:00 GMT

Photo credit Geof Sheppard, CC BY-SA 4.0. Brunel had been clear about the cost. The first decay always appeared where the legs sat in their cast-iron chairs, and around bolt holes, and under the decking that carried the ballast. Special gangs of men worked the viaducts year-round, replacing individual timbers without clo...

Image: Geof Sheppard | CC BY-SA 4.0

Cornwall Railway Viaducts: Coldrennick, 1897

Sat, 23 May 2026 00:00:00 GMT

Photo credit Derek Harper, CC BY-SA 2.0. On 9 February 1897, a gang of seventeen workmen were positioning a twenty-foot wrought-iron rail-bearer high in the seventh span of Coldrennick viaduct, near Menheniot. The platform they were standing on was supported by a second-hand timber beam, formerly used as a structural me...

Image: Derek Harper | CC BY-SA 2.0

Cornwall Railway Viaducts: Moorswater, the Most Spectacular

Sat, 23 May 2026 00:00:00 GMT

Photo credit Unknown author, Public domain. John Binding, who wrote the definitive study of Brunel's Cornish viaducts, considered Moorswater the most spectacular of all of them. It carried the line over a deep valley half a mile west of Liskeard, 147 feet high and 954 feet long, supported on fourteen buttressed piers. In 1...

Image: Unknown author | Public domain

Cornwall Railway Viaducts: What Survives

Sat, 23 May 2026 00:00:00 GMT

Photo credit Valentine & Sons, Public domain. St Pinnock viaduct, at 151 feet, was the tallest on the line. It was converted in 1882 by raising the brick piers and replacing the timber with iron girders, and is still in service - though the line was singled across it in 1964 to reduce the load, and again across neighbouring ...

Image: Valentine & Sons | Public domain