Figure 74. — Model of Pennsylvania Atlantic-type locomotive, 1907. 



The original locomotive was built at the railroad's Juniata 

 shops, Altoona, Pa., in August 1907, construction No. 1734. 

 Originally a class E3d locomotive, it was converted to an 

 E3sd in June 1913 by the addition of a superheater in the 

 Wilmington, Del., shops of the road. 



In a letter to Askew (Dec. 14, 1922) the chief of motive 

 power of the Pennsylvania System, J. T. Wallis, stated that 

 the cylinders of the original had a bore and stroke of 22 and 

 26 inches. The drivers were 80 inches in diameter and the 

 boiler carried a steam pressure of 205 pounds. The boiler 

 had a minimum (internal) diameter of 65V2 inches, and it 

 contained 170 2-inch flues and 24 5y2-inch flues, while the 

 superheater consisted of 96 iy2-inch flues. The distance be- 

 tween flue sheets was 180 inches and the total heating surface 

 was 2,571 square feet. The grate was 111 inches long and 72 

 wide. 



The total weight on the drivers was 127,200 pounds, on 

 the engine truck 35,500 pounds, and on the trailer truck 

 33,900 pounds — or a total of 196,600 pounds in working 

 order. The weight of the tender in working order was 134,000 

 pounds. The tractive force of the locomotive was 27,409 

 pounds. 



In his letter Wallis also made the following statement to 

 explain the significance of the modification of this class of 

 locomotive: 



93 



