The Washington State Department of Transportation (WSDOT) is responsible for maintaining 7,000 miles of highways and 3,300 bridges and tunnels, including the longest and widest of the world's first floating bridges. WSDOT also operates the state's most popular tourist attraction — the Washington State Ferries — with 29 boats that carry more than 27 million passengers. WSDOT is also a partner with Amtrak in providing the Amtrak Cascades passenger rail service connecting Seattle and other western Washington cities in the Vancouver B.C./Portland, Oregon corridor. With local transit agencies it helps provide bus and other transit services. WSDOT also runs 29 freight railroad cars that carry grain in Eastern Washington and operates 16 emergency airfields.