MRTA Purple line southern extension (Tao Poon - Rat Burana) has the total length approximately 23.6 kilometers with 17 stations, comprising 10 underground and 7 elevated stations. NCE provided the value engineering design for the elevated viaduct section from Dao Khanong to Khru Nai, which is approximately 9.34 kilometers long, together with a train depot, and 4 park-and-ride buildings. The main structure, running along the center of existing Suk Sawat road, is designed as precast prestressed concrete box girder viaduct for double tracks, with a typical continuous span of 40 meters supported by single bored pile. Additionally, balanced cantilever bridges with spans of 60-80 meters are adopted at locations required longer crossings.