John is fascinated by all of the vent stacks around the city liberating steam into the atmosphere and has been asking various people what it’s for – you know what he’s like. Apparently it’s the NY steam system which carries steam under the streets of Manhattan as a means of heating or cooling buildings. The system is old and leaks badly so wherever there is a leak, Con Eddison erect an orange and white stack to vent the steam and then walk away. Every street seems to have one or more!