See which subway is busy. Then what?

The Beijing subway system has come up with a way to help passengers beat the crush by showing them in real time how crowded subway lines are.

Passenger information for the city's 19 subway lines can now be found on the system's website, and the function will be added to its official app in the near future to allow subway users easy access to passenger load information using smartphones.

Subway lines are marked in four colors - black, red, yellow or green - depending on the number of people on board. Black indicates a line that is very crowded; red and yellow means less so; and green indicates the fewest passengers.