In message .com,
TheOneKEA writes

It can have as many as you want. Heathrow T123 has 2.

And the Next Train Out doohickey doesn't work right either...

Actually it does - as soon as a train gets the signal to leave, the
other train (assuming there is one in the platform) becomes the 'next
train' and indicates as such, as the driver of that first train should
now be closing the doors and be on his/her way, and all passengers
arriving on the platform should be directed to the other train to allow
this to happen. The fact that some drivers sit about for 2 minutes or
so doesn't change the fact that they should not now be there and the
other train is the 'next train out'
--
Steve Fitzgerald has now left the building.
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