The project feasibility study was conducted by Thai Government with the association from West Germany Government in 1971 which led to establishment of Expressway Authority of Thailand under Clause 39 of the Announcement of the Revolutionary Council Decree 290 dated 27 November 1972 (B.E.2515) to responsible for planning and construction of expressway and mass rapid transit projects.

The project was awarded to SNC-Lavalin, and the contracts for a 30-year operating concession and construction were signed in May 1990 at Queen Sirikit National Convention Centre.

Subsequently, the Cabinet passed a resolution approving the continuous study, promotion, and support for the creation of the master plan starting from 1994.

This revised master plan included monorail and light rapid transit lines to enhance Bangkok into a rail transportation metropolis.

The master plan outlines a mass transit network in areas anticipated to experience continuous and increasing land use in the future.

These lines are categorised into three groups as follows; In 2006, the Cabinet revised the previous BMT master plan with the aim of expanding coverage to more areas in Bangkok.

The study was to be conducted in collaboration with the Japan International Cooperation Agency (JICA)[9][10] to plan and support the necessary budget for investment, should there be a need to secure foreign loans for the project.

Additionally, the Mass Rapid Transit Authority of Thailand (MRTA) proposed 8 new lines to be included in the master plan, resulting in a total of 11 initial routes.

However, due to changing circumstances, the Department of Rail Transport (the current status of the OTP) reconsidered the entire M-Map 2.