Garabit Viaduct

The Garabit viaduct carries a single railway track across the gorge of the Truyère in the Cantal, high in the Massif Central. Its centre is one great parabolic arch of wrought iron, 165 m wide and 52 m high, painted red and set against green hillsides. The whole structure is 565 m long. When the trains first crossed it, the deck stood about 122 m above the river, and for a time it was the highest viaduct in the world. Its arch was the longest ever built until the Dom Luís I Bridge in Porto overtook it in 1886.

The idea came from a young state engineer, Léon Boyer. He argued that the Marvejols–Neussargues line should stay up on the plateau and leap the gorge at full height rather than wind down into the valleys. For the bridge itself the state turned to Gustave Eiffel's company without competitive tender, because Eiffel had just built the Maria Pia Bridge over the Douro in Porto, which posed the same problem. Maurice Koechlin did the structural engineering. Construction took place between 1880 and 1884, and the line through the viaduct opened in 1888. Eiffel's calculations proved exact: a passing train deflects the deck by about 8 mm, just as he had predicted. Boyer did not live to see the opening. He died in Panama in 1886, and a plaque of 1984 on the approach thanks him on behalf of the people of the Cantal.

The landscape around the bridge has changed since then. The Grandval dam on the Truyère, finished in 1959, flooded the valley into a reservoir about 28 km long, so the viaduct now crosses a lake about 95 m below the deck. The deck rests on seven iron piers, the tallest about 80 m, and the whole is a listed historic monument, fully protected since 2017. It also played the doomed bridge in the 1976 film The Cassandra Crossing. From the banks of the lake it is easy to see why it is counted among the finest iron bridges of the nineteenth century: a light, precise line drawn across heavy mountain country.

Getting there

The viaduct is near Ruynes-en-Margeride, roughly 15 km south of Saint-Flour. The nearest city with more than 15,000 people is Issoire, 63.5 km away. Aurillac Airport (AUR) is 60.3 km away. The A75 motorway passes close by, and the Aire de Garabit rest area, a few kilometres south of Saint-Flour towards Montpellier, has views of the bridge and a visitor centre, the Maison du Cantal. There is also a small café at the foot of the bridge on the D909, and a lookout on the far side of the river gives one of the best views.