EMD E units were the backbone of the Pennsy's passenger fleet.

Freight Locomotives

The PRR acquired hundreds of EMD F-units beginning in July of 1947. Complicating matters for railfans and modelers alike are the many "phases" of units that the railroad purchased. This document intends to point out the spotting features across the various models and phases.

There were 1807 F3/F5 units built, of which the PRR purchased 146 (8%). There were 3849 F7 units built, of which the PRR purchased 164 (4%). There were 372 FP7 units built, of which the PRR purchased 54 (15%).

The PRR did not purchase any of the earlier FT's or F2's, nor the later F9's, FP9's, or FL9's.

Road numbers in bold are in my personal collection (or on order).

EMD F3, Class EF15

The EMD F3 is a 1,500-horsepower B-B freight- and passenger-hauling diesel locomotive produced between July 1945 and February 1949 by General Motors’ Electro-Motive Division. Final assembly was at GM-EMD's La Grange, Illinois plant. A total of 1,111 cab-equipped lead A units and 696 cabless booster B units were built.

The F3 was the third model in GM-EMD's highly successful F-unit series of cab unit diesel locomotives, and it was the second most produced of the series. The F3 essentially differed from the EMD F2 in that it used the “new” D12 generator to produce more power and from the later EMD F7 in electrical equipment. Some late-model F3's had the same D27 traction motors, along with the heavier-duty electrical cables, used in the F7, and were referred to as model F5 by EMD's Engineering Department.

The F3 used a 16-cylinder 567B series diesel engine developing 1,500 hp at 800 rpm. The 567 was designed specifically for railroad locomotives, a supercharged 2 stroke 45 degree V type with 567 cu in displacement per cylinder, for a total of 9,072 cu in. A D.C. generator powered four traction motors, two on each Blomberg B truck. EMD has built all of its major components since 1939.

As built, the only way to distinguish between the F2 and F3 was the nose number panels on the A units, which were small on the F2 and large on the F3 and subsequent locomotives. However, these could and were often altered by the railroad. Few F2s were built, however.

Early versions of the F3 had the "chicken wire" grilles along the top edge of the carbody. Later production featured a distinctive fabricated stainless steel grille.

All F-units introduced after the FT have twin exhaust stacks and four electrically powered radiator fans arranged close together atop their roofs, unlike the FT's four stacks and separated and belt driven pairs of fans.

F3 Phases

The identification of locomotive "phases" is a creation of railfans. EMD used no such identification, and instead only kept track of the marketing name (e.g. F2, F3, F7, etc.) and individual locomotives' build (serial) numbers. During the production cycle of a particular model, as design and production techniques improved, all builders would invariably make minor changes. To better keep track of noticeable, and not so noticeable differences in appearance that a locomotive model would acquire during the course of its production run, locomotive historians began documenting any subtle or minor changes made to a particular diesel locomotive model as "phases", and referring to these as such. This practice has proved very popular over the years among diesel locomotive modelers looking to create the most "true to life" models possible.

Despite not being official designations, phase descriptions are quite useful to the diesel spotter and record keeper, but sometimes tricky as many of the changes described are mostly cosmetic and easily altered features of a locomotive - roof fans, body panels, grilles, etc. that could be - and often were - updated or swapped interchangeably during production runs.

The following are normally identified as F3 phases:

Phase I
Built from July 1945. High, flat-topped 36 in (914 mm) roof fans. Top third body panel had "chicken wire" in openings only. Short rear vent panel. Center-third body panel with three equally-spaced porthole windows and D17 traction motors. As-built Phase I F3 units are identical to the F2, they differ only in electrical equipment and numberboard size. Three highly modified locomotives survive from this series, rebuilt as FP10s, all for Metro-North Railroad.

Phase II (early)
Built from February 1947. Top third body panel now had full-length "chicken wire". Long rear vent panel. Center third body panel now had two portholes; area between covered with chicken wire, over 4 smaller rectangular openings.

Phase II (late)
Built from December 1947. Roof radiator fans change to low, pancake fans.

Phase III
Built from March 1948. (Surviving F3's former BAR 42,44,46 are still Phase 2 and were built in MAY 1948) Center third body panel now has no chicken wire between the portholes; the four rectangular openings now have louvres.

Phase IV
Built from August 1948. Chicken wire upper-third panel is replaced with full-length horizontal stainless steel grille.

"F5"
The first "F5A" EMDX demonstrator #59 was built in March 1948. Production of the "F5" started in August 1948 through the end of F3 production in February 1949. The difference between the "F5" and the F3 were the D27 traction motors with heavier-duty cables and higher capacity traction motor blowers fitted. Nearly all previously built F3's received the same upgrades by 1955. A total of 381 F5As and 238 F5Bs were produced. The note in the January 1, 1959 EMD Service Department Locomotive Reference Data states, "All F5 locomotives were delivered as F3 units." All EMD DC traction motors are backwards compatible so as the better motors became available the D37, D47, D57, D67 and D77 all could be found on an F unit.

PHASE CHART: EMD F2, F3 & F5 DIESEL LOCOMOTIVES All Phases here include rectangular-slit type dynamic brakes on both cabs and boosters. Original tables developed by Jim Fuhrman with details supplied by Ed Hawkins and John Thompson.
Designation	F2	F3 Phase1	F3 Phase 2 Early	F3 Phase 2 Late	F3 Phase 3	F3 Phase 4	"F5"
Dates	Jul 46 to Dec 46	Nov-Dec 46>>	Feb-May 47>>	Dec 47-Apr 48>>	Mar-Jun 48>>	Aug-Nov 48>>	October 48 to Feb 49
Radiator Fans	High, flat-top 36"			Low-pan-top 36"
Top-third panel	Chicken Wire in openings only		Full Chicken wire at top third panel			Horizontal Stainless Steel Grille
Rear vent opening	Short		Long
Center-third panel	Three equally-spaced portholes		Chicken wire between two portholes covering 4 rectangular openings		4 horizontal louvers between two portholes
Electrical	Same as FT	D17 traction motors					D27 traction motors  w/heavier cables
Number Boards	Same as FT	Small, streamlined four-digit (see Note 2)
Air Horn	N/A	Leslie single-note Tyfon A-200 (single, facing forward) Sample
PRR Roster	none	none	6 A units 8 B units	16 A units 17 B units	9 A units 7 B units	24 A units	25 A units 12 B units
PRR Photo	N/A	N/A
Notes:  1. All F2-F7 Boosters have 3 equally-spaced portholes in the center third panel.  2. While most roads opted for a large, angled number board, the PRR purchased the standard streamlined (small) four-digit numberboard.  3. F3 Phase IIb: Hirsimaki's Black Gold, Black Diamonds, Volume Two indicates (p. 42) that the helper units were not equipped with trainphone antennas. But we know from photo evidence that the units were so equipped, but as delivered did not have trainphone antennas. This initial A-B-A helper demonstrator set was delivered to the PRR in January 1948. They served on the Pittsburgh Division and were retired in December 1962. Also during an overhaul in August of 1956 helper unit 9519A was rebuilt to F-5 specifications with heavier traction motor cables, a prime mover from unit 9782B, and the front replacement porthole panel from a phase 2 F-7A thus eliminating the chicken wire in this area of the carbody. It was reclassified EF15a.  4. F3 Phase IV (F5): For the Pennsy the F-5 units went to work as "Snappers," the F-5 program never impacted the through freight units. Jack Consoli contests the generator as being one of the changes in this phase. However, the fact remains that, for the most part, these units appeared the same externally as the Phase IV's.  5. The InterMountain F3's in Pennsy livery have incorrect (angled) number boards. It is also worth noting that the parts sprue used to manufacture this locomotive also contains the high fans required for a Phase IIa depiction.

EMD F7, Class EF15a

The EMD F7 is a 1,500 horsepower Diesel-electric locomotive produced between February 1949 and December 1953 by the Electro-Motive Division of General Motors (EMD) and General Motors Diesel (GMD).

The F7 was the fourth model in GM-EMD's successful line of F unit locomotives, and by far the best-selling cab unit of all time. In fact, more F7s were built than all other F units combined. It succeeded the F3 model in GM-EMD's F unit sequence, and was replaced in turn by the F9. Final assembly was at GM-EMD's La Grange, Illinois, plant or GMD's London, Ontario, facility.

The F7 differed from the F3 primarily in internal equipment (mostly electrical) and some external features. Its continuous tractive effort rating was 20% higher (e.g. 40,000 lb for an F7 with 65 mph gearing, compared to 32,500 lb for an F3 with the same gearing).

The F7's prime mover is a 16-cylinder 567B series Diesel engine developing 1,500 hp at 800 rpm. The 567B is a mechanically aspirated two-stroke design in a 45 degree Vee configuration, with 567 cu in displacement per cylinder, for a total of 9,072 cu in. A direct current generator that is mechanically coupled to the flywheel end of the engine powers four traction motors, with two motors mounted on each Blomberg B truck.

There are no easily identifiable differences between late F3 production and early F7 production; the major differences were all internal electrical system changes. However, no F7 had "chicken wire" grilles of most F3s, and no F3s had later F7 changes described below under Phases.

Phases

The identification of locomotive "phases" is a creation of railfans, although now used in Diesel Spotters Guide. EMD used no such identification, and instead kept track of the marketing name (F7) and individual locomotives' build numbers. During the production cycle of a model, EMD would often make detail changes that were not readily apparent to the casual observer. To keep better track of the variations of locomotives identified the same by the manufacturer, railfans began referring to phases (critical changes to a locomotive line).

Despite not being official designations, the phase description is useful. However, many of the changes described are cosmetic, easily changed features of a locomotive: e.g., roof fans, body panels, grilles and the like could be and sometimes were updated or swapped. Most of the phase differences on the F7 were concerned only with A units; B units varied far less. The following are normally identified as F7 phases:

Phase I (early)
Built from February 1949. Upper grille with horizontal openings. Four horizontal louvred openings on center body panel. 36-inch dynamic brake fan, if dynamic brakes fitted. Flush windshield gasket changed to raised in July 1949. Square cab door corners with kick plates on the steps beneath. Wing window short with square corners. Single drip strip over cab windows and door. Square end door window. Round sand filler cover. Rear overhang.

Phase I (late)
Built from March 1950. Upper grille started out horizontal, as in early Phase I; from March 1951, some locomotives were built with vertical-slotted "Farr-Air" grilles, and by October 1951, all had them. Cab doors became round-cornered, and the kick plates were deleted. The wing windows became taller, with round corners. Two drip strips; one over cab windows, second over door. The end door window became round after November 1950.

Phase II
Built from February 1952. All upper grilles vertical "Farr-Air" type. Center car body louvres became vertical-slotted. Sand filler now with a horizontal, rectangular pull handle. From June 1952, 48-inch (1,219 mm) dynamic brake fans began to be introduced; from October 1952, all dynamic-brake equipped locomotives had them. At that latter date, locomotives no longer had a rear overhang.

PHASE CHART: EMD F7 & F9 DIESEL LOCOMOTIVESF7 & F9 cabs and boosters---features as delivered:  Original tables developed by Jim Fuhrman with details supplied by Ed Hawkins and John Thompson.
Production phases	F7 Phase 1a (Early)		F7 Phase 1b (Late)		F7 Phase 1c (Late)			F7 Phase 2 to Dec 1953			F9 to Apr 1957
Dates	Feb 1949>>	July 1949>>	Mar 1950>>	Nov 1950>>	Mar 1951>>	June 1951>>	Oct 1951>>	Feb 1952>>	June 1952>>	Oct 1952>>	Jan 1954>>
Grille	horizontal				horizontal or "Farr Air" vertical		vertical	vertical			vertical
Louvers	4 horizontal							4 vertical			5 vertical
DB fan	36"							36"	36"/48"	48"	48"
Windshield gasket	flush	raised						raised			raised
Door corners, Kick plates	square. yes		round, no					round, no			round, no
Wing window	short, w/square corners		tall, w/round corners					tall, w/round corners			tall, round corners
Drip strip	single		split, with rounded corners over door					split, with rounded corners over door			split
End door window	square			round				round			round
Sand filler cover	round							pull handle			pull handle
Rear overhang	yes							yes		no	no
Number Boards	Small, streamlined four-digit		Large, angled five-digit
Air Horn	Leslie single-note Tyfon A-200 (single, facing forward) Sample	Nathan 3-chime M3 (three, forward facing stub bells) Sample	N/A	Leslie Tyfon 3-chime A-125-3E Chime Tone(three, single-note horns, center facing rearward)		N/A	Leslie 3-chime S-3J (three, forward facing bells, center bell set higher) Sample	N/A	N/A
PRR Roster	20 A units 15 B units		27 A units 15 B units	none	68 A units 28 B units		none	8 A units 18 B units		none	none
PRR Photo				N/A			N/A			N/A	N/A
Notes:  1. F7s all rated at 1500 hp.  2. Boosters all have 3 portholes instead of louvers.  3. F7 Phase Ia: Initial Pennsy units featured streamlined (small) numberboards. As of July 1949 they switched to the 45-degree, four-digit numberboards. Greg Martin indicates that these units' windshields had raised, exposed gaskets.  5. F7 Phase IIb/IIc: EMD offered a larger dynamic brake package (with 48" fans) but the PRR didn't purchase it.  7. Not long after purchase, the units with the rear overhang had their overhang cut off.

Helper Service Locomotives

EMD F3 and F7, Class EH15

Dual Service Locomotives 

EMD FP7, Class EFP15

The EMD FP7 is a 1,500 horsepower, B-B dual-service passenger and freight-hauling diesel locomotive produced between June 1949 and December 1953 by General Motors' Electro-Motive Division and General Motors Diesel. Final assembly was at GM-EMD's La Grange, Illinois plant, excepting locomotives destined for Canada, in which case final assembly was at GMD's plant in London, Ontario. The FP7 was essentially EMD's F7A locomotive extended by four feet to give greater water capacity for the steam generator for heating passenger trains.

While EMD's E-units were successful passenger engines, their A1A-A1A wheel arrangement made them less useful in mountainous terrain. Several railroads had tried EMD's F3 in passenger service, but there was insufficient water capacity in an A-unit fitted with dynamic brakes. The real breakthrough came when EMD recognized the problem and added the stretched FP7 to its catalog.

A total of 381 cab-equipped lead A units were built; unlike the freight series, no cabless booster B units were sold. Regular F7B units were sometimes used with FP7 A units, since they, lacking cabs, had more room for water and steam generators. The FP7 and its successor, the FP9, were offshoots of GM-EMD's highly successful F-unit series of cab unit freight diesels.

F3s, F7s, and F9s equipped for passenger service are not FP-series locomotives, which, although similar in appearance, have distinctive differences. This includes, but not limited to, the greater body length. The extra 4 ft of length was added behind the first body-side porthole, and can be recognised by the greater distance between that porthole and the first small carbody filter grille. The corresponding space beneath the body, behind the front truck, was also opened up; this either remained an empty space or was filled with a distinctive water tank shaped like a barrel mounted transversely.

The first two PRR ABA sets (9832A-9832B-9833A and 9834A-9834B-9835A) were painted in the passenger scheme of Tuscan Red with five Buff stripes. The remaining units were painted in the standard freight scheme.

Nathan M3 air horns.

Passenger Locomotives

EMD E7, Class EP20

The E7 was a 2,000-horsepower, A1A-A1A passenger train locomotive built by General Motors' Electro-Motive Division of La Grange, Illinois. 428 cab versions, or E7As, were built from February 1945 to April 1949; 82 booster E7Bs were built from March 1945 to July 1948. (The 2,000 hp came from two 12 cylinder model 567A engines. Each engine drove its own electrical generator to power the two traction motors on one truck. The E7 was the eighth model in a line of passenger diesels of similar design known as EMD E-units, and it became the best selling E model upon its introduction.

In profile the front of the nose of an E7A was less slanted than on earlier EMD passenger locomotives, and the E7, E8, and E9 units have been nicknamed “bulldog nose” units. Some earlier units were called “shovel nose” units or “slant nose” units.

EMD E8, Class EP22

The E8 was a 2,250-horsepower, A1A-A1A passenger-train locomotive built by General Motors' Electro-Motive Division (EMD) of La Grange, Illinois. A total of 450 cab versions, or E8As, were built from August 1949 to January 1954, 447 for the U.S. and 3 for Canada. And 46 E8Bs were built from December 1949 to January 1954, all for the U.S. The 2,250 hp came from two 12 cylinder model 567B engines, each driving a generator to power the two traction motors on one truck. The E8 was the ninth model in the line of passenger diesels of similar design known as EMD E-units. Starting in September 1953, a total of 21 E8As were built which used either the 567BC or 567C engines.

In profile the front of the nose of E7, E8, and E9 units is less slanted than earlier EMD units, and E7/8/9s (and their four axle cousins, the F-unit series) have been nicknamed "bulldog nose" units. Earlier E-unit locomotives were nicknamed "slant nose" units.