Bangkok is a rapidly expanding city with a high population density. The government has established development guidelines for the city and its surrounding provinces, namely Phra Nakhon Si Ayutthaya, Chachoengsao, Nakhon Pathom, Samut Sakhon, Samut Songkhram, and Ratchaburi. The focus is on developing an integrated rail mass transit system to facilitate travel, promote the distribution of residential areas and employment centers, reduce transportation costs, lower energy consumption, and enhance the quality of life of the population. This approach is in line with the 20-Year National Strategy on Enhancing National Competitiveness.

The State Railway of Thailand (SRT) has implemented the Red Line suburban railway project, with some sections already in operation since 2021, while additional route extensions are currently under development. The Salaya–Nakhon Pathom suburban railway project is a key extension intended to connect the transport system in Bangkok and its metropolitan area and to support the national railway network in line with the R-Map concept. Since the previous study, conducted in 2007, contains outdated information, the SRT is required to appoint a consultant to review the design and prepare new bidding documents so that they are consistent with the current environment and present needs, and to support the approval process for the subsequent construction project.