The State Railway of Thailand (SRT) started its first operation in the Northern Line, Bangkok -Ayutthaya under the name of Royal State Railways of Siam (RSR) in 1897. Six years later, the Southern Line, Bangkok Noi (Thonburi) -Phetchaburi became effective. Rail transport system in Thailand was inspired when King Mongkut was given a gift of a model railway from Queen Victoria in 1855. Yet, the concrete actions were taken during King Chulalongkorn era. Served as one of the oldest transport forms in Thailand for 125 years, SRT has been making great efforts on three-dimensional railway development covering infrastructure, service, and commercial property to follow strategic goals of Thailand’s Transport Infrastructure Development Strategies 2015–2022 including promoting social stability, boosting competitiveness, augmenting economic stability, and promoting transport security and safety. Among others, SRT projects include double-track projects, high-speed rail projects, purchase of new rolling stocks, Red Line Extension commuter.