#2 is a "Thermos Bottle" or "Fireless" locomotive. The locomotive differs from a regular steam locomotive, because it is incapable of producing its own steam. Designed to be smokeless and safe, expelling no fire or sparks. The boiler is two-thirds filled with water and then steam is injected into the boiler from a central power plant boiler. As the steam dissipates, the water in the fireless boiler is turned into additional steam. The engine weighs 140,000 pounds. #2 was last used at Union Electric's power plant in Venice, Illinois.