Bridges presentation
railways. Examples in Europe include the Viaduc de Barentine (1846), constructed by British
navvies under the direction of MacKenzie and Thomas Brassey in brick rather than stone, and the
Viaduc de Saint-Chamas (1847), both in France. In the United Kingdom, notable viaducts include
the 181ft (55m) Ballochmyle Viaduct (1848), designed by John Miller for the Glasgow & South
Western Railway, the largest masonry-arch span in the country; the Harrington Viaduct (1876), the
longest at 3500ft (1067m), carried on 82 brick arches; the Meldon Viaduct (1874), the best surviving
iron viaduct in Devon; and, in concrete, the Glenfinnian Viaduct (1898), which has 21 arches of
mass-poured concrete.
Most notable of the early trestles was the Portage Viaduct in the USA (1852), a remarkable timber
structure designed by Silas Seymour, carrying the Erie Railroad over the Genessee River, 234ft
(71m) above the water and 876ft (276m) long (Figure 14). It was destroyed by fire in 1875, to be
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