EMD F5

The designation F5 was never an officially released or widely marketed locomotive model from General Motors' Electro-Motive Division in the way that the F3 or F7 were. Rather, the F5 designation arose internally within EMD's Engineering Department to describe certain late-production examples of the F3 that incorporated upgraded components originally developed for the subsequent F7 model. Specifically, these locomotives were equipped with D27 traction motors and the heavier-duty electrical cabling associated with the F7, setting them apart from standard F3 production units even though they were outwardly similar in most respects. Because these upgrades emerged gradually during the tail end of F3 production rather than representing a clean break into a new model, the F5 label remained an informal internal designation rather than a formal product offering. Adding further complexity to the designation's history, EMD occasionally applied the F5 name to Phase IV F3 carbody units, which featured a stainless steel grille in place of the wire mesh used on earlier production phases. This cosmetic and engineering overlap between the Phase IV F3 and the informal F5 categorization meant that the term was used inconsistently even within EMD itself. Neither usage of the F5 label was ever made official or carried through to sales literature or formal classification in the way that surrounding F-unit models were documented and marketed. The legacy of the F5 designation persists primarily as a topic of interest among historians and enthusiasts studying the transitional period of F-unit development in the late 1940s. Because the locomotives that might be called F5s were effectively delivered and operated as F3s, their service history is intertwined with that of the broader F3 fleet. They ran in freight and passenger service across numerous American railroads during the postwar dieselization era, indistinguishable in day-to-day operation from their more conventionally designated counterparts.

The locomotives informally designated as F5 shared the fundamental mechanical architecture of the EMD F3, including the 16-cylinder 567B prime mover producing 1,500 horsepower at 800 revolutions per minute. The distinguishing technical feature was the substitution of D27 traction motors in place of the units found in standard F3 production, along with the adoption of heavier electrical cables capable of handling the demands associated with F7-grade equipment. These components were mounted on Blomberg B trucks in the standard B-B wheel arrangement, with two traction motors per truck. The combination of the 567B engine with the upgraded electrical and traction equipment placed these units in a transitional position between the F3 and F7 in terms of their internal specification, even though their rated output remained consistent with standard F3 production. The carbody design of the Phase IV units sometimes associated with the F5 designation featured a stainless steel grille along the upper edge of the carbody, replacing the wire mesh arrangement seen on earlier F3 production phases. Like all F-unit A units of this period, the locomotives used a streamlined carbody construction suited to both freight and passenger assignments, with gearing options available to tailor performance for either service type. The maximum speed with passenger gearing was reportedly in the range of those achieved by contemporary F-unit models, and the overall platform proved robust enough that many examples remained in service with their original owners and subsequent operators for decades following initial delivery.

Models by: Athearn