NYC’s subway train riders stay cool, as London’s sweat

Commuters crammed inside hot and clammy underground trains into London's financial center over the last few months may be wondering what life could be like working in another city.

While climate change is raising temperatures everywhere, cities like Beijing or New York offer more air conditioned transportation systems capable of keeping their commuters cool. Passengers on London's busy Central line, for one, have endured heat wave conditions underground every day this summer, according to data recorded by Bloomberg.

The line's deep, narrow tunnels trap heat from the surface as well as subway car brake heat. As first reported by Bloomberg News in June, temperatures inside the uncooled cars can climb 9 degrees Farenheit compared to above the surface.

Using an Aranet4 sensor, Bloomberg has