The Mallet compound locomotive marks one of the most successful attempts of the locomotive designer and builder. It surpasses anything thus far built in size and combination of new ideas in design. The one shown in the illustration was built for the Erie Railroad for heavy pushing service. It has a boiler diameter of 84 inches and carries a steam pressure of 215 pounds per square inch. The boiler contains 404 two and one-fourth inch flues 21 feet long. Its high-pressure and low-pressure cylinders are 25 and 39 inches in diameter, respectively, having a common stroke of 28 inches. The drivers, sixteen in number, are each 64 inches in diameter. The total weight on the drivers is 410,000 pounds. The boiler has a total heating surface of 5313.7 square feet, 4971.5 of this number being in the tubes and 342.2 in the fire-box. The firebox is 126 inches long and 114 inches wide, giving 100 square feet of grate area. Its maximum tractive effort is 94,800 pounds.

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This page last updated 9/6/99