The Tsing Ma Bridge is a bridge in Hong Kong. It is the world's seventh-longest span suspension bridge. The bridge was named after two of the islands at its ends, namely Tsing Yi and Ma Wan. The two decks carry both road and rail traffic. The bridge has a main span of 1,377 metres (4,518 ft). The span is the largest of all bridges in the world carrying rail traffic. What is the curve of the supporting cables? A freely hanging cable assumes the form of a catenary, but a cable supporting the deck of a suspension bridge like this actually takes the form of a parabola.
