Reversing Falls Railway Bridge, Steel truss bridge in Saint John, Canada

The Reversing Falls Railway Bridge is a steel truss bridge carrying a single-track line over the Saint John River at the Reversing Falls, just before the river enters the Bay of Fundy. The present span, opened in 1922, replaced an 1885 bridge of the same length, 372 metres, built immediately upstream of the Reversing Falls road bridge.

The original structure dates to 1885 but underwent complete reconstruction in 1922 to handle growing rail traffic and heavier train loads. This major rebuilding allowed the bridge to meet new transportation demands of that era.

The bridge is named for the Reversing Falls, the tidal rapids it crosses just above the Saint John River's mouth. Its 1885 builder, the municipally owned Saint John Bridge and Railroad Extension Company, was set up to join the two halves of the old European and North American Railway. The New Brunswick Railway bought the company after the bridge opened.

The bridge crosses the Saint John River just above the Reversing Falls, at the river mouth into the Bay of Fundy, so it is seen from the banks and viewpoints near the falls rather than walked. It carries a single-track line of the New Brunswick Southern Railway, so access onto the deck is not open to visitors.

In 1976 NB Power built the Lorneville Pipeline from Irving Oil's Canaport tanker terminal at Red Head to the Coleson Cove Generating Station, and it crosses the Saint John River on this bridge. The City of Saint John also runs water supply pipes across it.