The Red Line commuter train system is a suburban rail project under construction in Bangkok Metropolitan Region, Thailand. The project is part of Bangkok’s Mass Rapid Transit Master Plan, which aims to develop an urban rail transit network to serve the Greater Bangkok area, the political and economic centre of Thailand and home for 10 million people. The Red Line will connect the Bangkok region with north, east, south and west suburban areas. It is expected to serve 131,000 commuters a day when it starts services in 2019, 262,000 passengers a day by 2029, and 336,000 people a day by 2034. The project is expected to take four years to complete.

The Bangkok rail system currently operates three rail lines, including the Green Line, the Blue Line and the Airport Rail Link. However, due to the limited number of lines and poor connectivity between them, 75% of public transportation still depends on buses. The number of automobiles and other vehicles is also increasing, leading to traffic congestion and air pollution. The Red Line was proposed by the State Railway of Thailand (SRT) to address the traffic problems and encourage a shift from road transport to urban rail. The proposal was approved in 2007 and the first construction phase started in 2013. The Red Line project includes the North Line and West Line. The North Line will be a 26.4km line from Bang Sue, located in the centre of Bangkok, to Rangsit in the north. The 14.6km West Line will stretch between Bang Sue and Taling Chan.