A. W. STEVENS


| May/June 1972



A. W. Stevens & Son Engine

A. W. Stevens & Son Engine No. 1774 owned by Mr. Ira A. Prickett, Mt. Pleasant, Iowa. Courtesy of Ernest H. Casson, 909 Naperville Road, Wheaton, Illinois 60187.

Ernest H. Casson

909 Naperville Road, Wheaton, Illinois 60187.

The picture is a 9 H. P., A. W. Stevens & Son engine No. 1774, built in 1890 at Auburn, N. Y., and owned by Mr. Ira. A. Prickett, 800 E. Washington St., Mt. Pleasant, Iowa, and shown there by Mr. Prickett in 1970 with his grand-daughter, Sandra DeVol, on the engine.

The boiler is a locomotive dry bottom firebox type. The shell is 24' diameter, 86' long, with lap joint seam, 33-2' tubes 54' long, firebox 21' wide, 29' long, 27' grate to crown sheet. It is designed for 125 lbs. steam pressure and operated at 120 lbs. The heating surface is 102 Sq. Ft. Grate surface 4.23 Sq. Ft., firebox volume 9.5 Cu. Ft. When burning 85 lbs. of 11,500 Btu. lb. of coal per hour, at 72% boiler efficiency and steam at 120 lbs. pressure, feed water temperature 60°F., the boiler will produce 600 lbs. of steam per hour.

The engine is a single cylinder, 6' bore, 9' stroke, 'D' type slide valve with Arnold valve gear, reversing and cutoff adjustment. Belt work governed speed 250 RPM. on traction 240 RPM. At 240 RPM. and one-half stroke cutoff the engine will develop 21.2 indicated horsepower. At 75.4% engine mechanical efficiency the brake horsepower is 16.

The engine traction system is a two shoe band or flywheel clutch, a 16 tooth crankshaft pinion, an 84 tooth intermediate gear, 1 57 tooth differential spur gear, 16 tooth bull pinions, 62 tooth bull gears and 54' Dia. drive wheels with 11' rims. The engine is estimated to weigh 10,500 lbs. with fuel and water supply. The ratio of engine RPM. to drive wheel RPM., is 13.8 to 1. The road traction speed at 240 RPM. Engine speed is 2.75 MPH. The horsepower delivered to the drive wheel rims is 9. When the engine is traveling on a light clay loam stubble field at 2.75 MPH. it requires 525 lbs. tractive effort equal to 3.91 H. P. The net tractive effort at the drawbar is then 683 lbs. equal to 5.09 H. P. The engine is well kept by Mr. Prickett, who also operates other engines.

Engine construction and operating features by courtesy of Mr. Prickett. Performance calculations and submitted by Ernest H. Casson, Wheaton, Ill.