Two lines are already under construction, the Red and Green Lines, and two more lines are under consideration, the Purple and Blue Lines.
The 52.1km Red Line will have 29 stations, four of which will be underground. It will run the length of Dubai from the Deira side of the Creek to Jebel Ali near the border with Abu Dhabi. It is planned that the first phase will open in 2009.
The 17.6km Green Line will have 14 stations - six underground and eight at ground level. It will run on both sides of the Creek serving the Deira and Bur Dubai central business districts. In these areas the stations will be underground. Two major underground interchange stations will have direct connections to the Red Line. The aim is to open in 2010, one year after the Red Line.Outside the central business districts, the trains will run on elevated viaducts through stations, for which the design and aesthetics have been developed specifically to enhance the urban architecture along its corridor. Taxi stations and park-and-ride facilities are planned for key Metro stations. The driverless, fully automated trains will be fully air-conditioned and designed to meet Dubai's specific requirements. The trains will offer standard class with a women and children only section plus a first class section. Five-car sets will provide seating for 400 passengers and standing room for many more. Groundworks began in February 2006, centred around the 52.1km Red Line. In August 2006 a second contract was awarded for building the 17.6km Green Line. Tunneling works for the Red Line were completed in January 2008. Shipments of rolling stock have already started arriving in Dubai for testing this year.
The 49km eight station line Purple Line will connect Dubai airport with Al Maktoum International Airport. The line is likely to be extended to new developments at later stages. Starting construction in March 2009, Purple Line services are scheduled to begin in December 2012.The Blue line, which will initially be 50km long also connecting Dubai International Airport to Al Maktoum International Airport, is currently under study. It is likely to be extended from Dubai airport to Palm Deira and to other new developments towards Dubai waterfront projects. Dubai RTA expects 318km of metro lines to be in operation by 2020. To reduce further the city's reliance upon road transport, the ٌRTA is also considering adding 268km of light rail lines that will serve as feeders to Dubai Metro.