The BTS SkyTrain system operates in 2 lines with a total of 52 stations.
The Sukhumvit Line begins at Kheha Samutprakan Station and ends at Wat Phra Sri Mahathat 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, Paholyothin Road, Sanam Pao, Saphan Khwai , Chatuchak Park and Wat Phra Sri Mahathat. This line is approximately 44.12 kilometers long and offers 40 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 13 stations, including one interchange station (Siam).
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.