> If they have a track problem that far under ground, it's a serious heat wave. Unintuitively, parts of the London underground are notorious for being extremel

> If they have a track problem that far under ground, it's a serious heat wave. Unintuitively, parts of the London underground are notorious for being extremely hot. Especially the central line is super hot due to the material the tunnels are dug into being an extremely good insulator/heat store. https://www.forbes.com/sites/lauriewinkless/2017/06/22/sweating-on-the-underground-why-are-tube-tunnels-so-hot/ https://www.forbes.com/sites/lauriewinkless/2017/06/22/sweat...