MRT
The Metropolitan Rapid Transit or MRT is a medium-capacity rapid transit system serving the Bangkok Metropolitan Region in Thailand. The MRT system comprises two fully operational rapid transit lines and two fully operational monorail lines, with another rapid transit line (Orange) under construction. The MRT Blue Line, officially the Chaloem Ratchamongkhon Line, between Hua Lamphong and Bang Sue was the first to open in July 2004 as Bangkok's second metro system. The MRT Blue line is officially known in Thai as rotfaifa mahanakhon (รถไฟฟ้ามหานคร) or "metropolitan SkyTrain", but it is more commonly called rotfai taidin (รถไฟใต้ดิน), literally, "underground train" as it was distinguished from the BTS Skytrain by being completely underground when its first section between Hua Lamphong to Bang Sue opened.