The Lionel Pennsylvania GP-7 No. 2028 would be among the least decorative of this class of diesel. This engine was a "stripped down" version and lacked the headlight lenses, number boards, horn, and the fuel tank that housed the battery for the horn, ornamental horn (Note: in the picture to the left a horn has been added), and it was illuminated only in the cab. The lettering was rubber-stamped on and has often worn off, as has the PRR herald on the cab.

Lionel issued this diesel with a variety of sheet-metal frames that sometimes had rivets attaching the side hand rails, and sometimes there were three holes and no rivets, and there was also a variation that had neither rivets or holes. Available only in 1955, it had a MAROON body, a three position directional unit whose control lever was adjustable from underneath the chassis, and single vertical worm drive motor that powers two axles.

There are three variations:

Variation A: Has GOLD rubber-stamped lettering.

Variation B: Has rivet holes and welded hand rails with a TAN frame.

Variation C: Has YELLOW rubber-stamped lettering.

All of the Lionel GP-7 units will operate equally well on O Gauge and O27 Gauge track.