The MRT Blue Line or MRT Chaloem Ratchamongkon Line is Bangkok's third rapid transit line, following Sukhumvit Line and Silom Line of the BTS Skytrain. It is the first line of the MRT system and is operated by Bangkok Expressway and Metro (BEM). The line has a total length of 48 km (29.83 mi), operating as a semi-circle or spiral route from Lak Song to Tha Phra which also serves as a self-interchange station.