The J Church is a Muni Metro light rail line in San Francisco, California, mainly serving the Noe Valley and Balboa Park neighborhoods, connecting them to downtown. It began as one of San Francisco's streetcar lines in 1917, and was partially converted to modern light-rail operation in 1981, as part of the creation of the Muni Metro system in the late 1970s. While many streetcar lines were converted to bus lines after World War II, the J Church remained a streetcar line due to the private right-of-way it uses to avoid the steepest grades on Church Street, between 18th Street and 22nd Street. Buses cannot negotiate the grades, and the right-of-way is too narrow to accommodate anything wider than the streetcar tracks.