Little consolation when you're waiting 15 minutes for the R train on the sweltering platform, ugh. But yeah – sadly London's system used to be pretty cool, but

Little consolation when you're waiting 15 minutes for the R train on the sweltering platform, ugh. But yeah – sadly London's system used to be pretty cool, but the clay interior has acted like a battery, slowly absorbing the heat, and it simply can't absorb any more. It's a massive engineering problem (and oversight).