At one station, Fan Xiaoyun, assistant chief engineer with the Guangzhou Metro, points to some thin strips of metal up above the streetcars.
"You can see that as the train enters the station, it just lightly touches those contact strips, and in 20 seconds it's fully charged and ready to go to the next station," he says.
Instead of batteries, the trams have Chinese-made supercapacitors mounted on their roofs. They're charged in the time that it takes passengers to get on and off. Then the streetcars can move at nearly 45 mph.
