The MRT serves more than 240,000 passengers each day. It has 18 operational stations along 20 kilometers (12 mi)[1] of underground route. The Blue Line, officially the Chaloem Ratchamongkhon Line, is the only line currently in operation. As of 2011, two extensions of the Blue Line are under construction. When completed, the Blue Line will become a loop line around the centre of Bangkok, with an extension to Bang Khae on its western side. The MRT Purple Line is also under construction. It will connect Bang Sue with Nonthaburi in the north-west, and will be the first public transit line outside the Bangkok Metropolitan Administration.