Viaduc de Chanteloube, Railway bridge in Chorges, France

The Viaduc de Chanteloube is a 300-metre masonry arch bridge in Chorges, Hautes-Alpes, built for the never-completed Chorges–Barcelonnette railway. Its deck follows an inverted S profile with parabolic transitions and a constant 21 mm/m gradient from the Chorges side to the Hyvans side. The centre has six arches of 27 m span, flanked by two massive piers, four 9 m arches on each side and a solid approach span; the central arch once stood 61 m above the Moulettes torrent. The parapets are low, as the bridge was not meant for pedestrians or unguided vehicles.

Construction of the Chorges–Barcelonnette line began in 1909 and was interrupted during the First World War, then abandoned for good in 1935. The viaduct never received track or equipment and no train ever crossed it. When the Serre-Ponçon dam was filled, its nominal level of 780 m matched the altitude of the viaduct's eastern estacade, and the structure was submerged in 1961.

The viaduct takes its alternative name, pont des Moulettes, from the Moulettes torrent whose submerged ravine it crosses. It was meant to carry the Chorges–Barcelonnette line toward the Ubaye valley, but the project was abandoned in 1935 and no train ever ran. Today the site is used for swimming and boating, and when the reservoir drops the deck can be crossed on foot.

The viaduct is submerged in the Serre-Ponçon reservoir and only reappears when the water level drops, as during the 2003 drawdown (-35 m) and the winter of 2008-2009 (-22 m). The annual operating cycle of the dam often exposes the deck and the upper part of the arches, allowing visitors to walk across the structure. A water-sports area is laid out near the viaduct.

The viaduct follows the "Séjourné style": no corner chains thickening the facing, no projecting band on the intrados, and the small relieving arches are hidden by the spandrels. Its parapets are low because the deck was never meant for pedestrians or unguided vehicles. The central arch once stood 61 metres above the Moulettes torrent.