Smiths Falls Bascule Bridge
This Scherzer Rolling Lift bascule bridge is an outstanding early example of a novel concept in movable bridges, developed by William Scherzer, an American engineer. It combines the balanced counterweight of a conventional bascule bridge, with a unique rolling lift motion that all but eliminates friction. Erected in 1912-1913 to carry the Canadian Northern Railway main line across the Rideau Canal, a busy steamboat navigation system, the bridge was renowned for its ease and speed of operation, proving the efficiency of the concept.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.