The EMD F-unit, built by the Electro-Motive Division of General Motors, was "the diesel that did it" - vanquished the steam engine from American railroads. In 1939-40, a quartet of F-units barnstormed across 35 states, logging 83,764 miles on 20 railroads and proving once and for all that diesels were the wave of the future.

One of EMD's largest customers was the Pennsylvania Railroad. On Pennsy mainlines from the east Coast to Chicago, new EMD diesels displaced the Pennsy-designed steamers that had been the symbols of the "P Company." While other diesel manufacturers competed with EMD, the various versions of the ubiquitous F-unit - FT, F3, and F7 - became the icons of the diesel revolution. This set recreates the power and excitement of the Pennsylvania diesels that hauled freight westward over the Allegheny Mountains; our Proto-Sound version includes the authentic chant of an F3 motor, blaring horn, ringing bell, and other sounds including crew conversations.