The Seattle Monorail is the nation's first full-scale commercial monorail system. Built in 1962 along with the Seattle Center in Washington State, the 1.2 miles long monorail is a favorite part of the Seattle skyline and provides a fun, quick and convenient link from downtown Seattle to Seattle Center. The Monorail’s original purpose was to transport Century 21 World's Fair visitors between downtown Seattle's Westlake Mall and the fairgrounds at Seattle Center. Following the fair, the monorail system was turned over to Century 21 Corporation at no cost. Century 21 sold the system to the City of Seattle in 1965 for $600,000. Its operation was contracted to Metro Transit, then to a private firm managed by Seattle Center. Seattle’s monorail trains are the only Alweg trains currently in operation anywhere in the world. The Monorail system uses 62 pre-stressed concrete piers that support the two concrete beams on which the trains run. The entire line is elevated. Riding on 64 rubber pneumatic tires, the monorail runs on 700 volts DC power obtained through contact rails on the inside of the beam. Sixteen load-carrying tires ride on top of the beam, and 48 guide tires grip the sides of the beam. With a maximum speed of 50 mph, Seattle's monorail remains the fastest full-sized monorail system in the U.S. The trains feature large head end windows. Over the years, many plans have been put forth to extend the rail system, but each of them has hit a roadblock or is gathering dust on the authorities' table. City officials have long given the Monorail expansion the cold shoulder. On the other hand, the biggest patrons of the project have been Seattle's voters.