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'''London Buses route SL9''', formerly '''London Buses route X140''', is a ] contracted ] express bus route in ], England. Running between ] and ] bus stations, it is operated by ].
'''London Buses route SL9''', formerly '''London Buses route X140''', is a ] contracted ] express bus route in ], England. Running between ] and ] bus stations, it is operated by ].
The route commenced on 7 December 2019, originally numbered X140, as part of a reorganisation of routes in the lead up to the opening of the Elizabeth line. Route X140 was introduced as a limited stop service between Harrow and Heathrow Central bus stations and as a partial replacement for the all stops route 140, which was withdrawn between Hayes & Harlington and Heathrow at the same time. Route X140 was initially operated by Metroline.
The route operates at a frequency of a bus every 12 minutes on weekdays and Saturdays and a bus every 15 minutes on Sundays. Between the hours of 23:00 and 07:00, the route is covered by an all stops night service, numbered N140, running every 30 minutes between Harrow Weald bus garage and Heathrow Central bus station.