"Andy" wrote in message
oups.com

I don't know whther the ages of the trains on the Victoria has
anything to do with the temperature, but I would hope that the new
trains on the Victoria will be better designed for their underground
lifestyle.

The Victoria Line trains are of similar vintage (ie, similar traction
packages) to the Piccadilly Line, but being driven automatically
probably means that they are driven harder (ie, fiercer acceleration and
braking). But I think that the 'all underground' theory is almost
certainly the right one.