Difference between F3, F7, & F9 locos??

[cspmo]

QUOTE: the F7 have radiator grills behind the first porthole. The F9 have a radiator grill in front of the first porthole.

They are air intake lovers. Radiator intake are along top behind the Chicken wire or the gril.

QUOTE: Dynamic brake - 2 sizes

Not counting the FTs. they are 3 size.
Rectangle on the F2 through the last F3.
36 inch fan on the F7 phase 1.
48 inch fan on the F7 phase 2.

[M636C]

If you look at all the usual EMC/EMD model letters,

S = six hundred horsepower
N = nine hundred horsepower
T = twelve hundred horsepower
E = eighteen hundred horsepower

You can see that "T" for thirteen hundred and fifty horsepower was already taken.

F for fourteen huundred horsepower was still available.

The locomotives were normally sold as "fourteen hundred horsepower twin units" with drawbars between units hence "FT" but Santa Fe bought all their units with couplers, and these were originally called model "FS" for "fourteen hundred horsepower single unit". As most roads later fitted couplers, all these units became known as FT.

Later, just F was used. The final F units (FL9) were 1800 HP while the final E units were 2400 HP, showing that the letters soon lost their significance.

SW, which originally stood for "six hundred horsepower with welded frame" was used for all "switchers". In the same way, F later was accepted to mean "Freight." but it didn't originally mean that.

M636C

[Anonymous]

QUOTE: Originally posted by Don Gibson

EMD's 'F' (for freight) were improved FT's, and went through 'improvement' stages through the years:

Horsepower 1350 to 1500,
cooling fans - 2 types
Dynamic brake - 2 sizes
Radiator grills - 3 types
Optional Boilers (Santa Fe)
# of portholes
- All on basically the same body.

A book with pictures is what you want, or 'Highliner A&B bodies as a kit with parts to change F-2's up to a F-9

The predecessor FT's were origially designed as 1700 hp permantly coupled pairs to compete against current steam ehgines. Their lower maintenace, low end torque, and not needing water, won out. 'F' s were designed to be individually coupled like for more flexibility.

EMC became EMD upon purchase by General Motors.

I actually read somewhere that f stood for fifteen hundred horsepower, i do not know the truth in this however.

alexander

[Don Gibson]

EMD's 'F' (for freight) were improved FT's, and went through 'improvement' stages through the years:

Horsepower 1350 to 1500,
cooling fans - 2 types
Dynamic brake - 2 sizes
Radiator grills - 3 types
Optional Boilers (Santa Fe)
# of portholes
- All on basically the same body.

A book with pictures is what you want, or 'Highliner A&B bodies as a kit with parts to change F-2's up to a F-9

The predecessor FT's were origially designed as 1700 hp permantly coupled pairs to compete against current steam ehgines. Their lower maintenace, low end torque, and not needing water, won out. 'F' s were designed to be individually coupled like for more flexibility.

EMC became EMD upon purchase by General Motors.

[emdgp92]

Speaking of F units, don't forget about the FL9s. FL9s are longer than F9s, and have a six-wheel rear truck. These units can run on diesel power or an outside third rail. Originally ordered by the New Haven, they ended up under Penn Central, Conrail, Amtrak, and Metro-North. They've since been retired, or sold to new owners.

[DSchmitt]

One complication is that earlier locomotives somtimes aquired spoting features of later loco types during major repairs or rebuilds.

Sometimes people pick up on non relevant features and assume that they distingish types. For instance I have a book (reprint , origionally published in the 1950's) that says the visible difference between a GP7 and a GP9 is the a dynamic brake blister on the "9. I have seen this repeated elsewhere. This misinfornation probably started because Lional modeled the GP7 without dynamics and the GP9 with dynamics.

Also somtimes people mistake railroad specific features as loco type features.

[pcarrell]

If a picture is worth a thousand words, maybe this will help.

Here is an F9; (click any pic to enlarge)


Ind here is the cab;


And here is from the engineers seat;

[Anonymous]

The horse power was different in all true, but how can one tell a F7 from a F9 just by looking at it? Take a look at the sides............ the F7 have radiator grills behind the first porthole. The F9 have a radiator grill in front of the first porthole.
This is only apperance to the eye to tell what your looking at. Look up photo's of a F7 and F9 and you would see what I mean. If have to be pics of either side. The F3's and FT's looked different all around.

[Anonymous]

Bob K.

Great information for us rookie F-Nuts! I will be buying a F-Unit either F3 or F7 soon and had often wondered the difference myself.

Trevor

[GN-Rick]

F3s were 1500 HP, not 1350. The F2, (an interim model between the FT and F3)
were rated at 1350. The phase 1 F3 is the model that had 3 portholes on rhe
side panel, somewhat like the Bs, instead of 2 with wire screening between
them which were phase lls, as mentioned. The phase llls replaced the wire
screening between the portholes with louvers, and some had high fans..
Phase IVs, as mentioned, received stainless grilles instead of wire screen and
were equipped with low fans. The F2 shared the same carbody as the phase l
F3.

[keystonecrossings]

I have a table on my web site that shows the various spotting features...

http://kc.pennsyrr.com/motiveops/spotting_f.html

[bogp40]

QUOTE: Originally posted by SSW9389

F7s were 1500 horsepower, not 1750 horsepower.

The F5 is the same thing as what railfans call a phase 4 F3. The F5 had the same traction motors, cables, and blowers as the F7s. The F5s were built from August 1948 to February 1949. The term F5 was used by EMD's marketing team and is not an official locomotive designation.

The 1750 horsepower plateau was reached with the F9 locomotive in production from 1954 to 1957.

Thanks for the correction on the HP, didn't even see it late last night. Guess this is what happens when you hand copy a list of specs. Do you have any more info on the F-3 Ph1 and F-9?
Bob K.

[SSW9389]

F7s were 1500 horsepower, not 1750 horsepower.

The F5 is the same thing as what railfans call a phase 4 F3. The F5 had the same traction motors, cables, and blowers as the F7s. The F5s were built from August 1948 to February 1949. The term F5 was used by EMD's marketing team and is not an official locomotive designation.

The 1750 horsepower plateau was reached with the F9 locomotive in production from 1954 to 1957.

[Anonymous]

Bob:
Thank you for the data. I'm just getting to this modeling hobby and your information is very helpful. I plan on modeling the early '50s since my grandfather came out of retirement during the Korean War to engineer munition trains in the Northwest. I have pictures of him posing with a F unit and a smaller unit that I have not been able to identify yet. Again, thank you.

Wally

[bogp40]

Bill,
Welcome to the forum. EMD's "F" units were solely responsible for replacing steam from the first FT of 1942 to the last late phase F-7 and 9's of '53-54.
You don't ask about the FT. They were in 2 phases(different build dates, the phases you hear about are for modelers to distingui***he car body changes) The FTs show the large boxed radiators on roof the phase difference are the dynamic grid changes on roof detail. Chicken wire side grills.
The F-3s were in 4 phases. Not very familiar with Ph 1 (1946-7)most roads skipped to next phase. All as delivered F-3s were 1350HP the carbody changes are the most misunderstood between phases. The Ph2 (1947)had the chicken wire between the side portholes, 4 high shrouded roof fans(like Ph1) and dynamic brake grids(2 rectangular wire roof screens just behind the cab doors). The Ph3(1948) were the same as Ph2 only with low fans. Ph4(1948-9) had the chicken wire screens replaced w/ stainless steel grills with horizontal slits and the side chicken wire between the portholes was replaced with louvers. Still had the dynamic grids. The F-3 Ph4 look exactly the same as early F-7s except for the grids.
The F-7s were built in 2 phases and were upgraded electronics and a 1500HP prime mover. Ph1 F-7(1950-2) had the same horizontal slit stainless grills, same side louvers, but had a 36" dynamic fan. Ph2 early (1952) wre the same as Ph1 only received the vertical slit stainless grills, still had 36" fan. The late Ph2(1953) were the same as early ph2 only received a 48" dynamic fan.
I am not as familiar with the F-9 maybe others can fill us in on these.
You may hear of a F-5, these were sometimes termed by the shops refering to F-3s rebuilt to F-7 specs w/ upgraded electronics, MU capability and 1500HP.
Hope this helps. So I can assume that there is another F unit nut to join the ranks.
Bob K.
The F-7

[Anonymous]

What is the basic differences between F3, F7, & F9 locos?? Year produced, power, length of unit or ??