fare to continue downtown after the bustitution. This continued until January 1, 2007, when a new fare structure added free transfers when using a CharlieCard. Additional short turn trips between Oak Square and Kenmore at rush hour were cut in June 1971, and restored for mornings only in 1987. Morning-only Brighton Center–Kenmore trips were operated from September 1999 to June 2013. On September 1, 2008, due to overcrowding on the inner part of the route, the MBTA began operating the 57A Oak Square–Kenmore station short turn of the 57 during weekday rush hours. Approximately every other trip operates as a 57A during rush hours; during off-peak hours and weekends all buses run the full-length route. Route 57 operates as a busy key bus route, with headways between 10 and 12 minutes at all times (and equal headways on the 57A during peaks). , the 57 and 57A combined were ninth-busiest route on the MBTA system, with 10,094 boardings on an average weekday. Route 57 is based at the Albany Street Bus Facility during weekday rush hours and midday service, and is based at the Cabot Garage for evening, weekend, and holiday service. One early-morning trip, intended for MBTA employees but open to the public, continues to on Mondays through Saturdays as 193 Watertown Yard–Haymarket station. It was inaugurated along with several other routes by the M.T.A. in September 1960, though they were not listed in public timetables until September 1999. Express buses The portion of the route west of Brighton Center is also served by four express routes operate to downtown Boston and Copley Square: 501 Brighton Center–Federal Street & Franklin Street 502 Watertown Yard–Copley station; service suspended indefinitely 503 Brighton Center–Copley Square; service suspended indefinitely 504 Watertown Yard–Federal Street & Franklin Street The 501 and 503 serve the same local streets but the 501 operates to downtown Boston and the 503 to Copley Square; the 502 and 504 operate similarly. All four routes enter the Massachusetts Turnpike at the Newton Corner rotary. Express bus service from Brighton and Watertown began even while the "A" branch was still running. The 61 Watertown/Newton Corner-Downtown Boston via Mass. Turnpike route began in July 1967, with Saturday service added in March 1968. In December 1967, the 61 was renumbered as 4, and a new route 61 running from Oak Square to downtown via Brighton Center and Union Square, Boston and the Turnpike was