The E3 was an Atlantic that was built by the PRR parallel to its E2 that was largely similar, but had larger cylinders. Between 1901 and 1910, a total of eight E3, 114 E3a and 56 E3d were built in the Juniata shops at Altoona. With 80 inch drivers they could not produce a high tractive effort, but with the introduction of steel passenger cars this was offset by operating them double-headed.
After the more powerful E6 Atlantics had been introduced, the E2 and E3 were called “Light Atlantics”. Beginning in 1912 they were superheated and their boiler pressure was reduced from 205 to 195 psi. In this process, a total of 90 E2a, E2d, E3a and E3d became the E3sd. They were used until the thirties and all were scrapped.