The A1 nonstop bus from Hounslow West station to the Central Area started in about 1969, and ran until the Underground was extended about 10 years later. They used old London single-deck buses from the early 1950s (AEC RF type for the technically minded) with their whining transmissions and thundering engines, and some seats taken out for luggage racks and more standing room. Eventually it was found the Underground was not as universally convenient as hoped and a new express A1 bus was started, this time from Heathrow to Central London. This lasted until the Heathrow Express came along.