Viaduc ferroviaire de Nanterre, Railway bridge in Nanterre and Carrières-sur-Seine, France.

The Nanterre railway viaduct is a 450.5 m concrete box-girder bridge carrying the Nanterre-Université to Sartrouville line over both arms of the Seine, resting on Île Saint-Martin between Nanterre and Carrières-sur-Seine. Its deck has a raised solid parapet with evenly spaced rectangular recesses, and thick piers with angled faces stand below; overhead electrification masts rise above the parapet. Graffiti covers part of the parapet's outer face near the right bank.

The viaduct carries the Nanterre-Université to Sartrouville line, used by RER A and Transilien L, across both arms of the Seine via Île Saint-Martin. South of the viaduct, after crossing the A86 motorway, a junction lets trains head either toward the RER A central section at Nanterre-Préfecture or toward the Saint-Germain-en-Laye line at Nanterre-Université. Its tracks converge with those of the nearby Pont ferroviaire des Anglais a few hundred metres north-west, before Houilles - Carrières-sur-Seine station.

The viaduct carries both RER A and Transilien L trains, and its southern end, past the A86 motorway crossing, holds a junction where trains are routed toward Nanterre-Préfecture or Nanterre-Université depending on their destination. It stands beside the Carrières-sur-Seine motorway viaduct, and the lines of both structures meet a few hundred metres north-west before Houilles - Carrières-sur-Seine station.

The viaduct crosses both arms of the Seine via Île Saint-Martin, between Nanterre and Carrières-sur-Seine, immediately beside the Carrières-sur-Seine motorway viaduct. It carries RER A and Transilien L trains, so it is seen from the riverbanks and from the streets of either commune; the concrete parapet with its row of rectangular recesses and the graffiti on its outer face are visible from below.

The viaduct crosses both arms of the Seine by resting on Île Saint-Martin, and it stands just beside the Carrières-sur-Seine motorway viaduct. A few hundred metres north-west, its tracks converge with those of the Pont ferroviaire des Anglais before Houilles - Carrières-sur-Seine station.