Chiba Urban Monorail
Modern monorails depend on a large solid beam as the vehicles' running surface. There are a number of competing designs divided into two broad classes, "straddle-beam" and "suspended" monorails. The most common type is the straddle-beam, in which the train straddles a steel or reinforced concrete beam wide. A rubber-tired carriage contacts the beam on the top and both sides for traction and to stabilize the vehicle. The style was popularized by the German company ALWEG. There is also a historical type of "suspension monorail" developed by German inventors Nicolaus Otto and Eugen Langen in the 1880s. It was built in the twin cities of Barmen and Elberfeld in Wuppertal, Germany, opened in 1901, and is still in operation. The Chiba Urban Monorail is the world's largest suspended network.