The BTS SkyTrain system operates in 2 lines with an approximately 68.5 kilometers in length with a total of 60 stations.
The Sukhumvit Line begins at Kheha Samutprakan Station and ends at Khu Khot Station.
The line starts from Kheha Samutprakan traveling via Sukhumvit Road through Bang Na Junction to Ploenchit Road, Rama I Road, Phyathai Road, Victory Monument, then passes along Paholyothin Road, Sanam Pao, Saphan Khwai, Chatuchak Park, Ha Yaek Lat Phrao, Ratchayothin intersection, Kasetsart intersection, Anusawari Lak Si Circle, Saphan Mai, Yaek Kor Por Aor to Khu Khot, covering 3 provinces: Pathum Thani, Bangkok and Samut Prakan. This line is approximately 54.25 kilometers long and offers 47 service stations, including one interchange station (Siam).
The Silom Line begins at Bang Wa Station and ends at National Stadium Station.
The line starts from Ratchaphruek at the intersection with Phetchakasem Road, then passes along Ratchaphruek Road to the intersection with Wutthakat Road. The line then passes the Ratchada-Talat Phlu intersection to Tak Sin intersection, and then crosses the Chao Phraya River via Saphan Taksin to Sathorn Road. Curving left above Chong Nonsi, the line proceeds along Silom Road, passing Lumpini Park and on to Rajdamri Road. The line then curves left onto Rama I Road and interchanges with the Sukhumvit Line at Siam, before terminating at National Stadium Station. The Silom line is approximately 14 kilometers and serves 14 stations, including one interchange station (Siam) and Saint Louis Station.
The stations and track are built on a 9 meter wide viaduct, 12 meters above the road median. The structure comprises segmented concrete casts and was assembled span-by-span using dry joint and external post-tensioning within the gap of each segment. This method requires minimal construction time, ideal for the congested traffic environment of the downtown core. The viaduct support structure is made of cast concrete, 2 meters wide and 30 – 35 meters in length.
For the Silom Line extension from Tak Sin Bridge to Bang Wa ( Ratchaphruek-Phetchakasem), the cast-in–situ method is also used.