The 15km Line 2 will link Ain Sebaa in the east with the city's main hospital in the central district of Hermitage, running via El Badr, Laayoune, and Mers Sultan and interchanging with Line 1 at Abdelmoumen and Ibn Tachfine stations.
Preparatory construction including utilities diversion works began in May and major construction is scheduled to start next May.
Meanwhile, Line 1 will be extended 2km from its current southern terminus at Facultès to Laymoun and Lissasfa.
The Dirhams 3.7bn ($US 380m) expansion project is due to be completed by 2019.
