Originally Posted by Spiff
At terminal A, just head for the Skylink and choose the train headed in the correct direction (though either direction will get you to terminal D).
I'd be surprised if it took you longer than 10 minutes to arrive at terminal D from the time you walked off the plane.
Don't forget to check out the new AC and/or BA lounge in terminal D if your time/status/membership permits.
Skylink's longest ride going in either direction is posted as 9 minutes. Since A and D are pretty close to opposite one another, that plus a couple of minutes to get to Skylink from your gate, and another couple of minutes to get to your gate from Skylink. 15 minutes tops. Skylink beats the **** out of the old TrAAin.