Stuart writes
If TfL want a solution to the heat on the tube they should just take a
long hard look at Highbury & Islington:

Victoria Line platform - like an oven (it has always seemed to me to be
the hottest line on the network for no obvious reason)
WAGN platform right next door - like a fridge.

Don't really understand how there can be such a diffrence in
temperature in such a small distance

Tunnel size. Number of people. Proximity to tunnel mouth and the open
air.

There you are, three reasons.

--
Dave