London Buses route SL9, formerly London Buses route X140, is a Transport for London contracted Superloop express bus route in London, England. Running between Harrow bus station and Heathrow Central bus station, it is operated by London Sovereign.
The route has two stopping service equivalents, routes 140 and 278.
History
Route X140 commenced on 7 December 2019 as part of a reorganisation of routes in the lead up to the opening of the Elizabeth line partly replacing route 140. It was initially operated by Metroline. Upon being put out to tender, on 4 September 2021 route X140 was taken over by London Sovereign's Harrow bus garage.
Due to delays in the delivery of new Alexander Dennis Enviro400EVs for the route, London Sovereign initially operated it with Wright SRM bodied Volvo B5LHs.
On 26 August 2023, route X140 was renumbered SL9, becoming part of the Superloop network of orbital express bus routes.
Current route
Route SL9 operates via these primary locations: Harrow bus station South Harrow station Northolt station Hayes & Harlington station Heathrow Central bus station