aqueduct atlantic ocean bascule bridge bulk carrier canada southern railway canadian national railway control lock elevation expropriation first welland canal garden city skyway geographic coordinate system grand trunk railway kilometre lake erie lake huron lake ontario main street tunnel merritton tunnel metre mile montreal niagara escarpment niagara falls niagara river ontario penn central queen elizabeth way saint lawrence seaway ship canal swing bridge thorold tunnel tonne townline tunnel trent-severn waterway truss bridge tunnel united states upper canada vertical lift bridge watermill welland by-pass welland river wikimedia commons william hamilton merritt windoc