BEIJING, Sept. 28 (Xinhua) -- Beijing's No. 5 subway line, which runs through the heart of the city from north to south, is set to begin operation on October 7 after taking nearly five years to build.

The 27.6-km line has 23 stops and runs from Tiantongyuan North Station in northern Beijing's Changping district to Songjiazhuang Station in southern Fengtai district.

It meets with the city's east-west subway Line 1 and crosses the loop line - Line 2. Passengers on Line 5 can also transfer to Line 13, north Beijing's light rail link.

Construction of the new subway line began in December, 2002 and involved 12 billion yuan (about 1.6 billion U.S. dollars) in investment. Trial operation was launched in late June this year.

Equipped with a wireless communication network, live broadcasts will be provided on televisions installed in each subway car and passengers will never lose the signal on their mobile phones.

The subway cars are wider and taller than the ones operating on the older lines and are designed to reach speeds of 80 km per hour. Elevators designed to aid disabled people have been installed.

Urban planners say completion of the No. 5 subway line will greatly ease north-south traffic congestion.

Beijing now has four subway lines with a total mileage of 114 km and they transport about 1.15 million passengers daily, 15 percent of the total commuters.

According to the municipal government, Beijing will add three subway lines next year and the total mileage will reach 200 km.

By 2020, 19 subway lines totaling 561.5 kilometers will have been put into operation, which could make it the largest underground rail system in the world, according to Beijing's city planning authorities.

Beijing held a public hearing this week, proposing two new pricing systems that will lead to a reduction of subway fares, which is believed to help ease ground traffic congestion.