The MRT Purple line or MRT Chalong Ratchatham line is Bangkok's fifth rapid transit line, following the Sukhumvit Line, Silom Line, MRT Blue Line, and Airport Rail Link. The line is 23 km (14 mi) long, serving the north-western area of Bangkok running from Tao Poon to Klong Bang Phai in Nonthaburi Province.

The Sukhumvit Line is an elevated metro rail line of the BTS Skytrain in Bangkok, Thailand. From the central Siam Station, where it connects with the Silom Line, the line runs both northwards along Phaya Thai and Phahon Yothin Roads to Khu Khot in Lam Luk Ka District in Pathum Thani, and eastwards along Rama I, Phloen Chit and Sukhumvit Roads, through Bang Na District to Kheha Station in Samut Prakan. BTS daily ridership (2019) is 740,000 passengers per day.