Atherley Narrows Swing Bridge, Railway swing bridge in Orillia, Canada

The Atherley Narrows Swing Bridge is a railway bridge connecting two lakes and built from nine steel girder sections. The structure rests on eight steel pile foundations that anchor it to the lake bed below.

Between 1843 and 1964, three railway bridges were built at the Atherley Narrows, and a navigation channel was dredged; these works disturbed the Mnjikaning Fish Weirs. The present plate girder bridge was constructed in 1970, making it the fourth structure at the crossing. A 2010 railway inspection deemed the swing bridge unsafe, and in 2011 reports described the wooden timber cribbing at its base as decaying and shedding material into the water.

The bridge sits at a location long important to the Mnjikaning First Nation, whose members have fished these waters for generations. The construction and operation of this structure shaped the traditional waterways and cultural practices of this community.

The bridge remains in a locked open position and is no longer operational after the railway line was abandoned. You can view the structure from the surrounding shorelines where it spans between the two lakes.

Two of the support piers come from different construction eras, with one built in 1919 on wooden piles beneath the water. This mix of materials and building methods shows how the crossing was repeatedly reinforced over time.