The walk from Hilton to terminal 4 is not bad at all, but beware when you return to terminal 4 in the morning and catch the free train to terminal 3: sometimes it does not stop at terminal 3 but continues all the way to Paddington. Yes, I know, all you have to do is read the electronic sign next to the tracks, which lets you know the train's next stop. However, if you're rushing towards the tracks trying to catch the train before it leaves, you may forget to read... (this must happen quite frequently: the conductor was not surprised at all, did not charge me for the ride, and allowed me to board the next Heathrow-bound train as soon as I arrived at Paddington. Meanwhile, my flight to AMS was delayed, so, in the end, disaster was averted...
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