| Here is the upper illustration on page 65 of the "Pennsylvania Railroad Altoona Machine Shops Construction Number List: 1866-1904." It was compiled by Joseph D. Lovell, and published by the Library Of American Transportation during 1984. Photo Caption: "PRR No. 1502, a Class A-3 four-wheel switcher, was built in February 1900. This engine's classification reflects the new system instituted around the turn of the century in which the letter indicates the wheel arrangement and not a separate class of engine as the previous system did." |