Lines The Green and Orange Lines both begin at the Central station, under the Pilot Plan Bus Station in the centre of Brasília and run parallel up until the Águas Claras station. The Orange Line goes south to Samambaia. The Green Line follows to Ceilândia. The metro runs underground in Brasília (exception at Asa Sul station) and through the Central Sector of Taguatinga, at Praça do Relógio station. Elsewhere, it runs on the surface. Technical The supervision and control of the operation, which includes the subsystems of traffic, energy, and telecommunications, are run by the Operational Control Center (OCC), considered the brains of the Metro-DF. The control is fully computerized. Qualified professionals constantly monitor all train movements. All is done with the help of sensors installed along the tracks and an optical fiber communication system. The system allows reception and transmission of information between the OCC and the other components of the metro system, such as trains, stations and substations. The center receives real-time information on route speeds, time spent at stations, passenger flow, and energy supply routes. The electricity used by the Metro-DF is supplied by Companhia Energética de Brasília (CEB), directly from Furnas. It arrives at 13,800 V alternating current and is transformed by power rectifier substations along the lines of Metro-DF. The rectifier substations distribute 13,800 V for passenger stations, which is stepped down to 380/220 V to feed the equipment. The trains' traction systems are fed by 750 V. The electric current is sent to the third rail and is collected by shoes located on the sides of trains, providing power to their motors. Any movement of trains on the lines and yards, signaling systems, and auxiliary energy distribution function is under the command of the Operational Control Center (OCC). In exceptional situations, the OCC, in touch with teams of technicians and agents in metro stations and courts, uses this system to convey the necessary steps to determine alternative routes for trains. Rolling stock Its increasing use indicated the need to expand the original fleet of 20 four–car Alstom Metropolis trainsets. To deal with the increasing demand, 12 new four–car trainsets were purchased from Alstom, with the first arriving in the Federal District in June 2010, leading to a fleet of 32 trains in total. All trains go through a period of engagement and dynamic tests, where all components of traction, braking, signaling and communication will