The government of Thailand has committed to spending more than $21 billion to expand Bangkok’s rail transit system, anchored by a $1.3-billion hub station scheduled to open as early as next year.

Intended to address the city’s notorious air pollution issues, the project calls for optimizing the metro area’s existing system with 10 electric-powered train routes, initiating a gradual phase-out of diesel-powered locomotives that, combined with automobile emissions, regularly make Bangkok one world’s five worst cities for air quality. The upgraded system could eventually carry more than 120,000 passengers per day once all elements are in place.

The plan also calls for modernizing rail connections between Thailand’s capital and most of the country’s major cities, where local transit systems will be converted to electric-power.

Government officials are counting on the major infrastructure investment to help lift Thailand’s economic fortunes, which have suffered from an extended drought and a coronavirus-related tourism decline.

Over the next three years, the Thai government plans to significantly expand both passenger and freight capacity by augmenting its existing 2,300-mile rail network with new tracks. Having been largely overlooked in favor of highways since the mid-20th Century, Thailand’s rail system could grow by 60% over the next 17 years with new routes added to tourist destinations and border towns.

Construction is already underway on Thailand’s first high-speed rail line, a nearly 380-mile project being funded by China as part of that country’s Belt and Road Initiative. Plans call for the rail line to connect with another China-built rail system underway in Laos. Other high-speed rail lines are contemplated to connect Bangkok with Singapore and other cities, with the Thai government looking to Japan to provide financial and technical assistance.