Those funny little numbers - what do they represent ?

[Anonymous]

According to the Kalmbach book "F Units, The diesels that did it", there were FP7s and FP9s, but no FP B units - FPs had a slightly longer carbody to accomodate the larger steam generator. Model Power? produce a rather nice FP in N scale - It has a diecast chassis, motor with twin flywheels - only snag is that the metal body tends to rattle against the metal chassis! Does anyone make a HO scale FP?

Interesting bit of trivia. No USA railroad bought FP9s - they were only sold in Canada and Saudi Arabia.

E's did come before F's in that EMD were making E-Units from 1936, while the FT demonstrator only appeared in 1939 - the FT did very nicely for EMC (as they were called then) during WW2 as they were the only company allowed to produce road freight locos - this basically gave them about 5-6 years head start over their competitors!

BB usually means a loco with hydraulic transmission, as opposed to BoBo which would be the same wheel arrangement but with conventional diesel-electric transmission. A1A refers to a loco with 3-axle trucks where the centre axle is unpowered and is only present to reduce axle weight - as in the E units.

Hope this helps with a few of the questions here!

[BR60103]

To make things more complicated, They made passenger versions of the F units, deignated FP7 and FP9 (maybe others). All CPR's A units were FPn, the B units were only FnB. The FP units were a few feet longer and had a boiler for heating the passenger cars.

[dehusman]

Actually the F doesn't stand for Freight. The early EMD system used the letter to stand for the horsepower:

S = Six hundred
N = Nine hundred
F = Fifteen hundred
E = Eighteen hundred

They abandoned the designations as horsepower improved and just kept the designation for the model type.

In switchers, EMD used both welded and cast underframes. So a 600 hp engine with a welded underframe was a model SW. A 900 hp engine with a cast underframe was an NC. EMD probably had one of the most complicated and non-intuitive model designation schemes of any of the builders.

Dave H.

[Anonymous]

I thought E's came before F's.

[bluepuma]

Looks like what is still missing are B trucks and C trucks and which ones are powered
vs. unpowered. What was that BB and CCC or A-1-A or things like the GG1.
Was that A and A, AA and AAA or ??? Axles powered and not.

[Wdlgln005]

The F3-F9's had one 16cyl diesel putting out 15-1800 hp to 4 traction motors.
The E's had 2 12cyl's with 2000 hp to 4 motors
It's the motors that pull the train.

It's the electric traction motors that pull the train. ATSF & other roads found that it was better to add another Funit with 1 crew to run the whole shebang. CGW was the Funit champ with up to 7 F's on freight.

When the passenger trains stopped running, the E's needed something else to pull to earn their keep. The freights may have been fast reefer blocks moving potatoes from Maine west & California fruit east. That's all done by truck now.

Get the Trains tape on E&F units. I'm watching trains videos for New Years!
Party safe & have a happy new year!

[Anonymous]

QUOTE: Originally posted by JimdeBree

If "F" stands for freight how come Santa Fe had all of those F units painted in War Bonnet colors pulling passenger trains?[?]

I also have seen pictures of Es units pulling freight. More railroads than SanteFe used F's for passanger service. EMD can build them but can't dictate to the railroad how to use em. So the railroads discovered F's were better than e's. In fact F's were just the best locos ever built. So they got used for lots of stuff. Sante Fe rebuilt most of their F-7s into CF-7 roadswitchers when cab units lost favor, that's how good they were. Small transferes and regional RR's still use CF-7s yet today, they are what, around 50 years old now? The same is happening now with F-40PH's and F-45s. Sante Fe (BNSF) uses them for freight in red warbonnet paint yet today. Just seen one the other day on an intermodal train with a couple SD-40s. I hear they pull out the steam generator and put in another fuel tank and concrete. FRED

[Anonymous]

If "F" stands for freight how come Santa Fe had all of those F units painted in War Bonnet colors pulling passenger trains?[?]

[sully57]

that clears up a lot. thanks to all! -Sully

[Anonymous]

The EMD (electro motive division) had two lots of locos in the really early days. These were teh F units and the E units. Your F3A is a freight unit (F, freight, gettit?). The E units were passenger units. You can tell the difference because the E units are significantly (1 and 1/2 times) longer and they have 3 axles on each truck rather than 2 on the F units.

The B means it is a booster unit. This means it is the same as an A unit but it does not have a cab so it can only go when it is connected to an A unit.

The EMD units had the following evolution:
FT
F2 (little used i think)
F3
F5
F7
F9

so an F7 is newer than an F3. The numbers are there to distinguish between different ages of locos. Frequently the newer locos are more powerful or have inovations like dynamic brakes (using the motors on the wheels as brakes, saving on brake wear) or turbo charging.

hope that answers some of your questions.
neil

[Anonymous]

F3A or F3B

F = Freight

3 or 7 = Model #

A = Loco with a cab (cab unit)

B = Booster or cab-less unit

There are times you will see A-B-B-A. This designates the locos used. 1 A unit, followed by 2 B units and then another A unit.

[sully57]

Now I know. Thanks all! Interesting site Paul! Just one more ques on numbers: A while back I bought a diesel loco (Proto 1000, I think it's called). It is an F3A. I have heard also about F7A as well. I understand the following car (following the loco that is), is sometimes referred to as "B". Is there an easy explanation as to what the middle (or even first) character means? Thank you again.

[Anonymous]

Yeh, I think you're talking about wheel arangments ex: Consolidation 2-8-0 or Decapod 2-10-0 or 4-8-4 Northern.

[IRONROOSTER]

This is known as the Whyte classification system for steam locomotive types. This page http://www.spikesys.com/Trains/loco_cls.html has the list , also diesels and electrics.
Enjoy
Paul

[Anonymous]

Are you referring to steam engine designations like 2-8-2 Mikado or 4-6-4 Hudson ?

That tells the number of Pilot wheels, Driver wheels, and Trailing wheels an engine has.

[sully57]

A real basic ques for anyone out there who knows... In Model RR books/ads/even this forum, what do the three sets of numbers refer to ? You know, the format is something like ### - ## - ### . Thank you.