Across the airport for nothing: the rail link between the terminals

Three stations under one airport

Heathrow has three railway stations, all of them below ground. Terminals 2 and 3 share one in the central area, between the two runways. Terminal 5 has its own at the western end, underneath the terminal building. Terminal 4 has the third, on the southern side, beyond the southern runway.

Two services link them at no charge for journeys that stay inside the airport. The Heathrow Express runs between the central station and Terminal 5. The Elizabeth line stops at the central station and then splits: one set of its trains heads for Terminal 4, another for Terminal 5. The Piccadilly line calls at all three stations as well, but it is the Underground, with its own fares and a slower way round, so the free trains are the ones to use.

How far the far end really is

On the train itself, Terminal 5 is a few minutes from the middle, and so is Terminal 4. The ride is never the problem. What adds up is everything around it: the walk from arrivals down to the platform, a wait of up to a quarter of an hour for the right train, the lift up at the far end and the walk on to a hotel or a check in desk.

Door to door, from the arrivals hall at the central terminals to the lobby of a Terminal 5 hotel, allow half an hour and expect twenty five minutes. Terminal 4 to Terminal 5 is the long one, because no train runs directly between them: change at the central station and allow forty minutes. That is still quicker than a taxi on the perimeter road at any hour when the perimeter road is busy, and it costs nothing.

Terminals 2 and 3 need no train at all. They share the central station, and the walk from one to the other runs through the passages beneath the central area, ten minutes or so with a case. For anyone moving between those two, the platforms are simply something to walk past.

Land at one end, sleep at the other

The useful thing about a free train is that it lets you choose a bed by where you leave from rather than where you landed. Arrive at Terminal 4 at nine in the evening, fly from Terminal 5 at seven the next morning, and cross on the train that same night. Sleep at TW6 2GD, whose enclosed walkway leads straight into Terminal 5, and the morning becomes a stroll rather than a transfer.

The same logic works in every direction. Land at Terminal 5 and fly from Terminal 2, and the hotel in the central area puts the check in desk a short walk from the bed. Land at the central terminals and fly from Terminal 4, and TW6 3AF on the Terminal 4 walkway does the same job.

Crossing on arrival rather than at dawn also removes the one real risk, which is the timetable. The rail link stops overnight, and the first and last trains shift from one timetable to the next, so check them on the day. A crossing made at ten at night, while the trains are running and the terminal is quiet, cannot be undone by a late first train in the morning.

Airside or landside

One distinction matters before any of this. A passenger connecting between two flights without entering the country stays airside and is moved between terminals by the airport's own transfer buses, with no train involved. The trains are landside. They are for guests who have passed through the border, collected any bag and are now ordinary visitors with a night in front of them.

If you are not sure which you are, the border tells you. Once you have walked past passport control and out into arrivals, you are landside, and the free trains are yours to use. How long that first walk takes, terminal by terminal, is worked through in the first hour after landing.

An overnight at the departure end

The shape that suits this arrangement best is the overnight to the first departure, at £1,800 on the ladder. You cross on arrival, check in beside the terminal you fly from, and she comes to you at a civilised hour of the evening. She leaves in the morning before the alarm, and your walk to check in is a matter of minutes.

Give the desk the hotel you will sleep in, not the terminal you landed at. She plans her journey to the building, by road or on the fast train from Paddington, and an evening at the Terminal 5 end is as simple as one at the central terminals once the hotel is named. For anyone coming in by the Underground, Hatton Cross, just outside the southern perimeter, is the Piccadilly line's doorway to the southern side of the airport.

Who works each end

Three of the five on the toned list know this layout particularly well. Angelika is the Terminal 5 specialist, happiest at the western end with Colnbrook and the walkway hotel close at hand. Laura lives beside Paddington and comes out on the fast train, so a hotel above one of the airport stations is the quickest place to meet her. Tina works every terminal on the airport and takes a change of building in her stride.

Tell the desk both terminals, the hotel you have chosen and the time of the morning flight, and it will say whether the evening fits. Every rung of the ladder appears on rates, and each step of a booking on booking.