Mumbai Metro is a rapid transit system serving the city of Mumbai, Maharashtra. The system is designed to reduce traffic congestion in the city, and supplement the overcrowded Mumbai Suburban Railway network. It will be built in three phases over a 15-year period, with overall completion expected in 2021. When complete, the core system will comprise three high-capacity metro railway lines, spanning a total of . Line 1 of the Mumbai Metro is operated by Mumbai Metro One Pvt Ltd (MOOPL), a joint venture company formed by RATP Développement, Transdev and Reliance Infrastructure, under a 35-year contract. MOOPL operates under the control of Mumbai Metro One Private Limited (MMOPL), formed by Reliance and the Mumbai Metropolitan Region Development Authority (MMRDA).