Boltar wrote:
I've noticed the victoria line seems to be much warmer than the other
lines these days (or maybe it always has been but I've not noticed).
Is this because the trains are more frequent , or they use up more
energy on ATO , or the tunnel ventilation isn't so good , or is there
some other reason?

Always has been hotter (well as long as i've been travelling on it).

I've asked this before on here, the answer i got was that it's to do
with the fact that the Vic line is completely underground and so the
trains don't have any fresh air to cool off in except when they go to
the depot.

It's really noticable at Highbury & Islington where the FCC platforms
are like a fridge in comparison