Until Sunday, travelers in the metropolis had to juggle multiple cards and tickets to navigate the sinuous network run by a collection of operators in the Japanese capital and its sprawling suburbs.

But the new Pasmo card lets travelers ride most buses and trains in the city, regardless of operator, by touching the cards on an IC chip reader that automatically deducts fares.

"This makes life so much easier. Until now, everything was so disjointed," said Yuichi Iiura, 18, a high school student in Tokyo who was about to get on a train from central Shimbashi station to meet friends.

"I'm glad the companies all came together like this."

The Pasmo also comes with an electronic money function that can be used to pay for goods at convenience stores and at automatic vending machines.

Greater Tokyo is the largest urban conglomeration in the world, with over 35 million inhabitants _ more than the number of Canadians, latest U.N. figures show.

The area's trains carried almost 14 billion people in 2005, according to Japan's Transport Ministry. Tokyo's largest terminal, Shinjuku, handles an estimated 3.5 million passengers a day and claims to be the busiest station in the world.