M J Forbes wrote:
In fact, it's normal to change the destination at (or just after
departing from) Hatton Cross, so that people waiting at T4 and
wishing to get into town don't get confused by a train turning up
with "Heathrow" on the front (at least, that's the way I used to do
it). The operational switch from WB to EB takes place at Heathrow
123. --

Cheers Steve - Hatton X WB would seem logical, but how many people
board at T4 for T123, especially when the HX is free between these
two points?


Passengers also board at T4's only platform for stations east of T123
therefore it makes sense for them to know where the train is going..