EMD "F" Units, Defining A New Era


Along with the Electro-Motive Corporation’s E series, the later EMD F series, built primarily for freight service, would become the principal diesel-electric model to spell  the end for steam. The Electro-Motive Corporation (EMC) has its beginnings in 1922 being based out of Cleveland, Ohio building inexpensive motorcars. With the purchase of the company in 1930 by General Motors, and more resources at its disposal the company began developing the precursor of the modern-day diesel-electric road unit (cabs and road-switchers), the streamlined trainset, which consisted of a powered car permanently attached to a few coaches (usually two or three cars). The most famous of these streamlined trainsets was the Burlington Zephyrs, a beautiful stainless steel creation (originally powered by Winton diesel engines, which would also become a subsidiary of GM) that was extremely lightweight and fast. 

The original trainset, the Zephyr 9900, made headlines in 1934 when it completed a non-stop journey from Denver to Chicago in a little over 13 hours.  Today, numerous F units remain preserved around the country, either in operation or as static displays.  A few even continue to pull freight trains!

Bangor & Aroostook F3A #40 lays over in Oakfield, Maine on a bright and sunny February 6, 1970. Roger Puta photo.








Because the power cars with these trainsets were permanently attached to the coaches EMC sought to design a locomotive free of this articulated setup but designed in such a manner that a railroad could still attach it to any passenger train and obtain the same, smooth streamlined look. This it did with the unveiling of the EA model in 1937, the first in a long line of passenger diesel locomotive designs that would come to be known as the E series.  Not surprisingly, soon after the EA unveiling the company decided to take things a step further and develop the first true diesel locomotive road unit, capable of pulling long freights in main line service. In 1939 it came out with the FT model (perhaps the key difference between the EMD F series and Es was that Fs rode on B-B trucks whereas Es rode on A1As [which was a three-axle truck with the center axle unpowered] and carried a noticeably longer carbody), the first in EMC’s F series, and one of the most success diesel-electric designs of all time.

It's the early Penn Central era and it appears a former Pennsylvania F7A (built as #9781 in February, 1951) is on its way to EMD as a trade-in unit. The locomotive is seen here at the 59th Street Yard in Chicago on April 9, 1970. Note the writing in chalk, "Ship To Electro-Motive Div. GMC, McCook, ILL., P.O. 7265." Roger Puta photo.

The FT design also employed the new dynamic braking system, which essentially was another means of braking that temporarily employed the traction motors as generators and used the resulting electromotive force to retard (or slow) the train (very efficient and effective).  The F series model would come to define American railroading for years and you can still catch Fs in regular use even today! The FT (which stood for Freight, Twenty-seven hundred horsepower) was a superb locomotive and although its 2,700 horsepower came from an A-B setup of a cab (A) plus booster (B), each rated at 1,350 horsepower, the model would be embraced by the rail industry for the efficiencies it held over steam power as well as being rugged and easy to maintain.

What remains of Monon's train #5, the southbound "Thoroughbred," kicks up the snow through Dyer, Indiana on February 10, 1963. Roger Puta photo.

Like with the EA model, the Santa Fe was the first to jump on the bandwagon with the FT and ordered a whopping 320 A and B units just by itself (it single-handedly purchased more FTs than Alco’s entire line of PAs), and it did not take long for other railroads to follow after seeing the locomotive’s capabilities. The FT became so successful that before 1950 EMC had sold over 1,000 units! The FT essentially became the standard by which all other similar cab models were designed by other manufacturers and it instantly made EMC the industry leader in diesel locomotives.

Rio Grande F9A #5771 awaits departure from Salt Lake City, Utah with train #18, the eastbound "Rio Grande Zephyr," during July, 1981. Roger Puta photo.

The FT’s success was only the beginning for the EMD F series. With the end of World War II wartime restrictions were lifted and EMC, by now known as General Motors’ Electro-Motive Division (EMD), was able to once again produce locomotives. The builder wasted no time ramping up production and soon unveiled the F3 (that followed the initial FT model) which sold some 1,111 units; the F7 followed next and sold 2,366 units; and last was the F9 which sold 87 units. Other than being upgraded to 1,500 horsepower (and 1,750 with the F9) over the FT’s 1,350 hp there were minor differences between the F3, F7 and F9 except for small overall changes and tweaks here and there. Amazingly all of these units were built in a time frame of a little over a decade, between 1945 and 1957. 

EMD F Series Line

Model Type Units Built Date Built Horsepower
FT555 A Units/541 B Units1939-19451,350
F274 A Units/30 B Units19461,350
F31,111 A Units/696 B Units1945-19491,500
F72,366 A Units/1,483 B Units1949-19531,500
FP73241949-19531,500
F9100 A Units/154 B Units1954-19601,750
FP9901954-19591,750
FL9601956-19571,750-1,800
F40C1519743,200
F40PH4111976-19923,000-3,200
SDP40F1501973-19743,000
F45861968-19713,600
FP45141967-19683,600
F59PH831988-19943,000
F59PHIStill In Production1994-Present3,200
F69PH-AC219893,000


A Soo Line F7A and GP7 roll northbound with a few boxcars after just clearing the Chicago & North Western interlocking (note the tower in the distance) at Shawano, Wisconsin in October, 1964. Today, the C&NW line is abandoned. Roger Puta photo.

Interestingly, later EMD F series designs included an FP model, the FP7 and FP9, which were essentially F7s and F9s except for an increased frame that allowed for a steam generator and added water capabilities for passenger service use. There were several built, over 400, but their numbers were far less when compared to the thousands of standard Fs manufactured.  The success of the EMD F series is still incredible, even today, as its sales only fell slightly below that of its later sister models; GP7s, GP9s and SD40-2s. Like those models, Fs continue to roam the rails and likely will continue to do so for many years to come; not only because of their rugged nature and ease of maintenance but also because of the unit's clean and timeless streamlined design, allowing it to be a good choice even today for freight and passenger service.




  1. Home
  2.  ›
  3. Diesel Locomotives
  4.  ›
  5. F Units

Header Photo: Drew Jacksich



Researching Rights-Of-Way

A popular pastime for many is studying and/or exploring abandoned rights-of-way.  Today, there are tens of thousands of miles scattered throughout the country.  Many were pulled up in the 1970's and 1980's although others were removed long before that.  If you are researching active or abandoned corridors you might want to check out the United States Geological Survey's (USGS) Historical Topographic Map Explorer.  It is an excellent resource with thousands of historic maps on file throughout the country.  Just type in a town or city and click on the timeline of maps at the bottom of the page!



Studying Diesels

You will be hard pressed at finding a better online resource regarding diesel locomotives than Craig Rutherford's TheDieselShop.us.  The website contains everything from historic (fallen flags) to contemporary (Class I's, regionals, short lines, and even some museums/tourist lines) rosters, locomotive production information, technical data, all notable models cataloged by the five major builders (American Locomotive, Electro-Motive, General Electric, Fairbanks-Morse, and Baldwin), and much more.  A highly recommended database!



Electro-Motive Database

In 1998 a gentleman by the name of Andre Kristopans put together a web page highlighting virtually every unit every out-shopped by General Motors' Electro-Motive Division.  Alas, in 2013 the site closed by thankfully Don Strack rescued the data and transferred it over to his UtahRails.net site (another fine resource).  If you are researching anything EMD related please visit this page first.  The information includes original numbers, serials, and order numbers.