BEIJING -- Beijing opened three new subway lines on Saturday morning to ease traffic during the Olympic Games.

An opening ceremony was held at Beitucheng Station, the transfer station of Line 10 and the Olympic Branch Line. Journalists and a limited number of local residents with intra-day tickets witnessed the scene. The other line opened was the Airport Line.

The three lines will begin carrying passengers from 2 p.m.

"Trains, staff, all kinds of materials and signal facilities are ready for passengers," said Jia Peng, spokesman of Beijing Subway Co. Ltd.

The new links, built at a total cost of 22.3 billion yuan (3.2 billion U.S. dollars), will increase the number of subway lines in the Chinese capital to eight and the total length of track to 200 kilometers from the current 142 km.

Trains would be running at an average interval of 3.5 minutes on Line 10, said Zhou Zhengyu, Beijing Municipal Committee of Communications deputy head.

Beijing traffic authorities were working on a subway line operation schedule for passengers shuttling between different Olympic venues, according to Zhou.

Beginning on Sunday vehicles with even and odd number plates will have to run on alternate days on Beijing's roads, and an additional 4 million people will resort to the public transport system.

The trains used for the new lines can carry 1,424 passengers each, or 344 more than those on other lines, said Zhou.

The Airport Line links the downtown areas with Terminal 3, a new terminal building at the Beijing Capital International Airport in the northeastern suburbs. Trains will be running at an average interval of 15 minutes, and the 28-km trip takes about 20 minutes, he added.

A public hearing early this month by the National Development and Reform Commission decided a reasonable fare for a subway ride to the airport should be around 25 yuan.

Beijing subway operators have estimated a daily maximum of 30,000 passenger trips on the Airport Line during the Aug. 8-24 Olympic Games, according to Liu Jian, deputy head of Beijing Mass Transit Railway Operation Corp. Ltd.

Subway builders have set aside room in the Dongzhimen Railway Station, the downtown end of the Airport Line, where in the future, passengers will be able to check in for their flights and have their luggage delivered.

But no time-table is immediately available as to when the check-in counters will be set up at the downtown subway station.

The Olympic Branch Line, running 4.5 kilometers, will carry spectators to the main Games' venues in northern Beijing, and Line No. 10 will run 25 km northwest to southeast in the shape of a right angle.

But before and during the Games, the Olympic Branch Line will open exclusively to participants to the Games, including athletes, coaches, journalists and others, and spectators holding tickets of the day, said Zhou.

"The passengers all need to receive security checks on the ground before they take the Olympic subway to the Games' facilities," he said.