In its basic form, a steam locomotive was a railroad machine that burned fuel with fire to heat water contained in a boiler to make steam, and that pressurized steam pushed against pistons that were connected to cranks on the wheels, causing them to rotate to produce power and the motion necessary to pull a train. Pretty basic, eh? Well, there was once a type of locomotive even simpler than that—it had no fire and did not burn fuel to boil the water!
Boiling is the physical process where a liquid (in this case, water) turns into a gas (steam) when heated to its boiling point. The boiling point of water is the temperature when boiling occurs. When molecules of a liquid are heated, they begin to move around and spread apart. If the molecules are heated to the boiling point, they will be able to spread out enough to change from a liquid state to a gaseous state—bubbles form and boiling occurs. At the normal atmospheric pressure of 14.7 psi (pounds per square inch) water boils at 212 degrees Fahrenheit.
However, pressure on the surface of water keeps the water molecules contained. When pressure is higher, it takes more energy (heat) to bring water to the boiling point. Inside a tightly sealed pressure vessel, the water is heated and eventually boils into steam. Since the steam cannot escape, it collects in the top of the boiler. All of those trapped water molecules in the steam increase the pressure inside the boiler, and boiling stops until the steam pressure is reduced. Water under pressure does not boil at 212 degrees F, and will not—cannot—produce steam at that temperature. When pressure is applied to water, its boiling point rises—the higher the pressure, the higher the boiling point. For example, if water in a boiler is under a pressure of 50 psi, the water will boil when its temperature reaches 281 degrees; under a pressure of 250 psi water will boil only at a temperature of 401 degrees.
Using this scientific principle of how pressure affects the boiling point of water, the commercial locomotive builders designed small switching locos that, when filled initially with a charge of hot water and steam, could continue generating their own steam for about 8 hours, and without the need for a fire. Such “fireless” steam locomotives were popular for use in areas where flammable substances were handled, such as in textile mills, chemical plants and coal-burning power plants. Nicknamed “fireless cookers” after the then-popular “pressure cooker” top-of-stove kitchen device, fireless locos operated without the need of a fire to heat boiler water to make steam. Instead, these engines were built with heavily insulated boilers to store both pressurized steam and hot water that were supplied from a separate source. Insulated boilers had to contain heat because there was no fire.
As a fireless cooker performs work and uses steam, its boiler pressure and boiling point of water are both reduced, thus allowing the superheated water inside the boiler to begin boiling again and make additional steam. Steam is produced, collected at the top of the boiler and is available to continue providing uninterrupted power for the locomotive. When the steam pressure rises again, the water stops boiling and the entire process is repeated over-and-over until there is not enough hot water remaining in the boiler to produce steam, even at low pressure. Then it was time for another injection of hot water and steam from the separate source to recharge the boiler. Typically, fireless cookers could be operated for about eight hours on a single charge of superheated water and steam.
On January 23, 2018, the Age of Steam Roundhouse acquired its 20th steam locomotive, former Columbus & Southern Ohio Electric Company 0-4-0F #2. Constructed by Heisler Locomotive Works in 1940, this fireless locomotive was used at C&OSE’s electric generating plant in Groveport, Ohio. It had 250 psi in its boiler, which was reduced to 75 psi for use in its 21”x20” cylinders to turn small 36-inch driving wheels. As such, #2 developed just 14,700 pounds of tractive effort. Though not very powerful, this fireless cooker had to move only a few loaded or empty coal hopper cars at any given time—why pay for more tractive effort than would ever be needed? Along with fireless sister 0-4-0F #1, these little locomotives were donated in 1965 to the Penn-Ohio Railfan’s Association, and they were stored out in an open field near Canfield. During 1974 loco #2 was acquired by and moved to the Old Express restaurant in Sharon, Pa. A truck stop company named Travel Centers of America acquired that property, and their new plans did not include this old locomotive. So, the Age of Steam Roundhouse offered to purchase this fireless cooker at scrap value and preserve it indoors at its beautiful loco display and restoration facility in Sugarcreek, Ohio. A highway truck backed-up to #2, and the 54-ton 0-4-0F was winched aboard the lowboy trailer for its 112-mile trip to AoSRH (since renamed Age of Steam Roundhouse Museum).