Routes have two-part names like "1 California" and "K Ingleside", where the second portion is usually a street served by the route (or in some cases, a neighborhood or landmark). Light rail and streetcar lines are lettered, while bus routes are numbered. The letter/number scheme was created by Muni, while the two-part naming scheme was created by the Market Street Railway, which Muni absorbed in 1944. The three cable car lines are largely known by name (Powell-Mason, Powell-Hyde, and California), though they are abbreviated to PM, PH, and C on maps, and have internal numbers 59-61 for operational purposes.