There is growing interest in using rail transit, trams, metros, light rail, to solve urban transportation problems, particularly road congestion and air pollution. In developing urban rail projects, a range of major cities around the world have turned to public-private partnership models, to leverage both public and private resources and expertise. Dissecting the successes and failures of public-private urban rail schemes, this note examines how policy makers can best deal with the main risks involved in designing, procuring, and implementing such schemes. It also draws lessons on best practice in developing and managing contractual arrangements that can help ensure their success and sustainability.