TOKYO - TOKYO on Saturday opened its first new subway rail line in seven years, connecting some of the Japanese capital's busiest areas in hopes of alleviating rush-hour congestion and stimulating the economy.

Packed with children and railroad buffs, the first car of the Fukutoshin Line, the ninth of the Tokyo Metro, rolled out on a sunny day in the latest addition to one of the world's busiest urban transport networks.

The 20.2km line connects some of western Tokyo's main areas including the bustling entertainment and business district of Shinjuku, the trendy young area of Shibuya and the middle-class hub of Ikebukuro.

It is the first new line opened by the Tokyo Metro since 2001. The capital also has multiple other operators of local lines.

Tokyo Metro forecast 150,000 passengers would use the line each day, easing pressure in a city notorious for cramped trains. It is aimed in particular at providing relief for the key Yamanote Line, which runs a loop around Tokyo.

Japan also hopes that the flurry of new stores opening in the stations will bring in shoppers, stimulating much-needed consumer spending in the world's second largest economy.

'A functional line linking the major bustling areas was born today,' Tokyo Governor Shintaro Ishihara told an opening ceremony.

'Tokyo is an outstanding city in terms of the number of train services, which will help give us a favourable reputation in the race to host the Olympics,' Mr Ishihara said.

Tokyo, which hosted Asia's first Olympics in 1964, is bidding for the 2016 Olympic Games against Chicago, Madrid and Rio de Janeiro. -- AFP