901 West Pratt St., Baltimore, MD 21223
Detailed Information

Object: Fireless Steam Locomotive, standard gauge. Acc. No. 1979.1027, Cat. No. 79.1027.01

Donor: Potomac Electric Power Co. (PEPCO), 1979.  

Purchased new by Potomac Electric in 1938.

Description: 4-wheel, 35-ton locomotive, manufactured in 1938 by the Heisler Locomotive Works, Erie, Pa., Heisler construction no. 43.       

Dimensions:  21 ft 4 in long,  11 ft 4 in high,  9 ft 6 in wide.

Photo attached to email with this memo (jpeg).

    Our Locomotive -    This locomotive has been stored at Silver Hill since its donation in 1979.  For the last two decades at least, it has resided in careful storage in Bldg 19, and it is in excellent condition.  Offered by PEPCO (Potomac Electric Power Co.; from its Alexandria, Va. power station), our specimen was collected by curator John H. White as an example of a rare type of steam-propulsion technology.  To historians of locomotives, of railroading as an industry, or of energy generation, the fireless is an albeit interesting but obscure variation on the technology of highly specialized locomotives.

    About the 'Fireless' Type in General -    As a type, the "fireless" locomotive was indeed highly specialized, and few were manufactured.  The Heisler Works of Erie, Pa., produced by far the greatest number of examples of the fireless type, about 50.  Such a locomotive could only operate on trackage very near a large, stationary steam plant, to which the locomotive would return every few hours of operation for hookup to the stationary plant's boiler - in order to recharge the locomotive with superheated water - i.e. liquid water heated under high pressure and thus to temperatures well above 100 degrees C.  (Superheated water contained in the cylindrical "pressure vessel" that is the principal visible feature of the locomotive provided the short-term source of steam to run the pistons to propel the wheels.  By opening the throttle, the pressure within the vessel of superheated water was slightly reduced, and the slightly lowered pressure resulted in the generation of water vapor - saturated steam at the new pressure - to push the pistons.)  There is no firebox to heat the water; hence the term, "fireless."

    In the US, fireless locomotives ran exclusively on the small network of tracks located within the boundaries of some of the largest coal-fired power stations operated by utilities.  Fireless locomotives were "mules" that shuttled loaded coal cars over distances of about a hundred yards from reserve coal-car storage tracks located within the power station's grounds over to the coal intake unit of the plant, and then moved the empty cars back to an outbound track within the plant grounds for pickup by a connecting railroad company's regular freight trains.  A fireless could not travel more than about five miles in total before requiring a re-charge of superheated water from its "host" plant. 

Moved to the B&O on August, 18, 2009.


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