BEIJING - A new subway line, which runs through the complex of stadiums, gymnasiums and parks for the 2008 Beijing Olympic Games, is to begin trial operation on June 1, a local rail traffic official said here on Saturday.

The Olympic Green station of Olympic branch line. [Xinhua]

Construction of the subway tunnel and stations has been completed, the official said.

The 4.4-km-long line starts from Beitucheng, near the northern fourth ring road, and travels underground through the gymnasium of swimming, the venue for the Olympiad opening ceremony, the Olympic Park and the Forest Park. It has four stops.

Beijing currently has 95 km of mass transit railway lines in operation, of which 54.15 kilometers were build underground.

The city will increase the number of subway lines to nine with a total length of 200 km by 2008, and bring them to 19 totaling 561.5 km by 2020, according to Beijing's city planning authorities.