F.Y.I. The Lechmere Viaduct has a drawbridge in it too. ( Street view --- > https://maps.google.com/?ll=42.367137,-71.069182&spn=0.000476,0.000708&t=h&z=21&layer=c&cbll=42.367137,-71.069182&panoid=wazYB6RJ59K2U022j-DD9g&cbp=12,43.05,,0,-8.35 ) Not sure if it is still functional though...