The MRT Purple Line (Thai: รถไฟฟ้ามหานคร สายสีม่วง) is a rapid transit line of the Bangkok MRT under construction for the Mass Rapid Transit Authority of Thailand (MRTA) in the Bangkok Metropolitan Region and Nonthaburi Province, Thailand. When it opens, it will be second line to be operated by MRT and the city's fifth rapid transit line. Following Sukhumvit Line, Silom Line, MRT Blue Line and Airport Rail Link. It is expected that the line will begin it's operation in late 2016.