Tags: Locomotive.
The Pennsylvania Railroad’s steam locomotive class D2 (formerly Class B pre-1895) comprised twenty 4-4-0 locomotives intended for mountain passenger helper service constructed at the railroad’s own Altoona Works during 1869–1880. They were the second standardized class of locomotives on the railroad and shared many parts with other standard classes.This design differed from the Class A (later D1) mainly in its smaller drivers for greater tractive effort in mountainous terrain.
