BEIJING - The subway line built to link Olympic venues in the north of Beijing will begin trial operation Monday, local traffic authority said Sunday.

A view of the platform of Olympic Green Station on Beijing Subway Olympic Branch Line is seen in this file photo taken on January 25, 2008. [Xinhua]

The 4.5-km Olympic Branch Line will open exclusively to workers, volunteers, media people who hold valid certificates issued by the Beijing Olympics organizing committee before August 8, according to the Beijing Municipal Committee of Communications.

After August 8, the opening day of the Games, spectators holding valid tickets can take the subway line for free.

All passengers should take security checks before they get on the Olympic subway to the Games' facilities.

The line started an unmanned trial operation on July 19.

The new line is under trial run and all equipment and services still need to be improved, according to subway operators.

Subway operators estimate the Olympic line would be transporting a maximum of 220,000 passengers daily during the Games.

The line, with four stops, starts from Beitucheng, near the northern fourth ring road, and travels underground through the gymnasium of swimming, the venue for the opening ceremony, the Olympic Park and the Forest Park.

Construction of the project began in mid 2005, which cost 1.4 billion yuan (195 million U.S. dollars).

Beijing, the host for the Olympics on August 8 to 24 and the Paralympics September 6 to 17, now has eight subway lines with 200 km of tracks, transporting millions of passengers daily.