What is the difference between Heathrow Underground and Heathrow train station?

One serves the Underground (Tube) system that covers London and the suburbs and the other serves overground trains that go everywhere else. You can get to all Heathrow terminals on the Underground and Overground trains.

Yes. When you leave terminal 123 underground stn turn right and follow the signs.

The Heathrow underground line is quite new and a branch off from the Piccadilly line.

Heathrow Underground Stations are on the Piccadilly Line of the London Underground. http://www.bbc.co.uk/london/travel/downloads/tube_map.gif Whereas Heathrow Term 1,2,3, Heathrow Term 4 and Heathrow Term 5 railway stations are served by Heathrow Express and Heathrow Connect from London Paddington. Heathrow Express is a non-stop service which takes 15 minutes to reach Terminal 1,2,3 whereas Heathrow Connect takes 32 minutes. The Underground is cheaper because Heathrow Express (owned by BAA) and Heathrow Connect (BAA/First Great Western joint venture) are open access rail companies so are free to price there own tickets independent of Tfl or the rest of the rail network and the line between hayes and harlington and heathrow is privately owned by BAA although Network Rail are responsible for maintenance on BAA's behalf. The tube is owned by TFL so accepts Oyster fares and all these fares are set by TFL and capped by the government which prevents them from being increase by more than a set % each year. The current level that fares can rise is Retail Price Index + 1% but the government are planning to increase this to RPI+3% next year. Heathrow Express and Heathrow Connect are free of charge for interchanging between airport terminals. London Underground have a station at Terminals 1,2 and 3 so that is where you will need to alight for terminal 3.

Calling the national rail system the 'overground' is incorrect. Heathrow Underground Station is the terminus of the London Underground (Subway) line the Piccadilly Line www.tfl.gov.uk Heathrow Railway Station is the terminus of the Heathrow Express and Heathrow Connect rail services from London Paddington www.heathrowexpress.com The price difference is because the Underground line takes 45 to 60 minutes to reach central London,serving many areas on route. The Heathrow Express train runs direct to Paddington Station non stop in 15 minutes You can get to Terminal 3 from either station. Just follow the signs

Hi gary Heathrow underground station actually is in the airfield strange as it might seem, here is the joke when you arrive the station is actually upstairs would you believe it you need to come down the stairs or down in a lift from the underground station. there are buses which do transfers from the station to all the terminals even terminals 3 and 4. This is england a sense of humour is required to be english.