The Erie Canal's Lock 8 on the Mohawk River includes a three-span movable dam measuring 510 feet wide that is often mistaken for a bridge and, when activated, raises and lowers boats by as much as 15 feet. Schenectady's Stockade District is the oldest residential neighborhood in the country, has been continuously inhabited for more than 300 years, and holds the richest concentration of historic period homes in the United States. Mohawk Harbor provides public access to the river with boating, events, recreation, restaurants, shopping, waterside hotels and apartments, the ALCO Heritage Trail, Rivers Casino & Resort, and Mohawk Harbor Arena, home of Union College hockey. Before Lions Park drew thousands to its riverside walking and cycling path, a busy railway line there carried passengers and goods between Schenectady and Troy, and the former Niskayuna train station is listed on the National Register of Historic Places.