Tube temperatures: A place where it's 30C in October
A few weeks ago I had a guided tour of a newly reopened Victoria line air vent in north London.
It's one of 13 that are being brought back into service by Transport for London (TfL) at a cost of £50m.
The problem it is trying to solve is that most of the deep lines, including the Victoria line, are getting hotter.
TfL is running more trains due to the upgrade, which generates more heat. Also, those new trains do seem to churn out the heat more than the old ones.
On Wednesday I measured the temperature outside Oxford Circus station and it was 10C (50F). Down on the Victoria/Northern line platform it was 30C (86F).
In the summer I measured it and it was 40C (104F).
Then TfL blamed the regenerative braking system that hadn't been turned on.
If it has now been turned on commuters (and staff) are noticing the line is still extremely warm and uncomfortable.
The idea is that these reopened vents will reduce the temperature by a few degrees and there are also plans for air conditioning units on some busy platforms - although that is some way off.