I seem to be in a minority of one in thinking the map is wrong, so I'll double-check next time I'm on an EL train before digging my heels in too much.
It seemed to me when I last looked at it that West Drayton is shown, correctly, as being in zone 6 and the Heathrow stations are clearly shown as being in a different zone than West Drayton (or perhaps no zone - it isn't clear). To my mind, that's wrong. Maps in trains do not purport to tell you what the single fares are - anyone who uses PAYG for non-TfL National Rail journeys or mixed mode TfL / NR journeys can attest to that.
They
do purport to tell you what zone stations are in, and the map in question fails to do that in the case of the Heathrow stations. And that has the obvious potential to mislead passengers holding a Travelcard or hoping to rely on daily capping based on the zones they have travelled in (hence this thread).
At its worst, it could cause somebody holding a Travelcard and wanting to go to Heathrow to alight at Hayes & Harlington, exit and then tap in on Oyster or Contactless, believing they'd reached the limit of their Travelcard's validity.
There is no reason why a text box couldn't have been added to the map explaining that special single fares apply to Heathrow, without messing up the way the zones are depicted.
HS1 is outside of the fare zones and therefore zonal fares do not apply, as I am sure you know.
Well, HS1 it goes to St Pancras, which is in Zone 1. I accept that Stratford International rail station (which is not in the Travelcard zones although it is shown in zones 2 and 3 on the Rail and Tube Services map) is technically separate from Stratford International DLR station (which
is in zones 2 and 3), but that is an artifice in many ways. Both are immediately adjacent to each other and have the same name.
Anyone looking at the rail and tube services map would expect to be able to use their Travelcard on that line, and would only realise they can't if they looked at the "fares information" box bottom left. If they fail to spot that, Southeastern do clarify the point that Travelcards are not accepted, quite forcefully, at their gatelines, to be fair. They draw rather less attention to the irregular fare they charge if you use contactless PAYG.