On Tuesday, the Thai cabinet approved three new rail lines worth over 70bn baht ($2bn), which they hope will encourage three million people per day to use public transport.
Two of the projects are light rail lines in Bangkok, a city known for its congested streets and backed-up traffic. Their combined value will be 65bn baht, said transport minister Thira Haocharoen.
The third rail line, costing 5.8bn baht, will link the eastern province of Chachoengsao to a deep-sea port, and bidding for all three is expected to start in July.
Construction will begin next year.
Bangkok's existing mass transit system has three lines – two above ground, and one underground – totalling 75km (47 miles) of tracks.
Together they carry almost 630,000 passengers a day.
Officials predict that at least three million people will use the capital's mass transit system when the two new city commuter lines with a combined track length of 41km are completed by 2010.
"They will take people from provinces neighbouring Bangkok and the suburbs to the centre of Bangkok in 40 minutes or an hour," said Pranote Suriya, a traffic planning official with the transport ministry.
