F40

[atsf sp]

Why is the passenger F40 just the F40 and not a FP40. The F45 had no HEP, where the FP45 did because it was passenger. Why was the P not incorporated into the F40 markings?

[DutchRailnut]

FP has nothing to do with passenger engines, FP is enlarged frame F unit, 4 feet longer than a standard F unit, the FL was 8 feet longer than a standard F unit.
Since the F40 was not lenghtened the FP designation would be wrong, same with the Boston FP10 misnomer, they were F10's as they were standard F unit lenght.

[MEC407]

Why was the P not incorporated into the F40 markings?

The P was was incorporated: F40PH (or the many variants... PH-2, PHM, PH-2C, etc... but all of them include the letter P).

The only exception to this rule is the F40C, which is a whole other topic. It should have had the letters PH in its name somewhere, due to being a passenger unit with head end power... but EMD is somewhat notorious for not following their own naming conventions.

[FCP503]

... but EMD is somewhat notorious for not following their own naming conventions.

Then there is GE that changes conventions every decade or so...

[ZephyrHogHead]

It was an F-40PH. In EMD talk it is broken down this way. F- denotes the type of body. F is used to denote a "car body" locomotive. 40- denotes that it is a 40 Series locomotive. P- passenger H- HEP. This way when you get an EMD unit if you know what all the letters in the model type mean you can figure out exactly what you have even without seeing it.

GE is different. They use horsepwer in their model numbers. Example P-42DC P- passenger 42 - 4,250 horse power (I know it seems wierd that they would use just 42) DC- Dierect Current.

[Allen Hazen]

Neither locomotive builder has been completely systematic and consistent in its nomenclatural conventions: forgiveably so, I think, since technological changes in the ninety years of diesel electric locomotive development (remember, GE built diesel electrics in 1918!) have been so extensive that it is hard to imagine someone at the begining of the history designing a convention that would still make sense today!

EMD has, notoriously, re-interpreted some of its letters: "SW" originaally meant 600 hp with a welded frame, but came to be generic for end-cab switchers of horsepower up to 1500 hp. In the case at hand, "F" almost certainly was originally (1940?) chosen for "freight," with "FP" a decade or so later for lengthened F-style units with steam boilers: it seems likely (though I don't have documentation) that the "P" was because the units could be used on passenger trains. Another two decades (almost: 1968) and-- the original "FP" designs being long out of production-- they recycled "FP" for cowl-body units with steam generators, and then "F" for freight-only SD types with cowls. Amtrak's 1973 "SDP40F" continued this use of "F" for cowl ("full-width"?) bodies; it would probably have been called an "FP40" except for a temporary legal requirement that it be deemed a modified old rather than a new design. When Metra bought similarly cowled SD units with HEP for Chicago commuter service in 1974, they were called "F40C": your guess as to whether "C" meant commuter or Chicago or something else.

GE's sins against nomenclatural consistency are different. They haven't even tried to have a distinct model designation for each design, and have happily applied the same designation to different designs. (This is more obvious when you look at their export locomotives in addition to the North American models: "U30C," for example, can be a North American unit from the 1960s/1970s with a 16-cylinder engine and 752 traction motors OR an export model from the 1980s/1990s with a 12-cylinder engine and 761 traction motors!)

One does have the feeling that the locomotive builders may not care quite as much as the railfans about model designations....

[ZephyrHogHead]

I honestly dont care on bit as long as I know what the horsepower is, how many cylinders, 4 or 6 axles, and dc or ac. When it comes to running a locomotive thats all I honestly care about.

In regard to the info that I gave regarding EMD and GE locomotive deisgnations I was only relaying what I was tought in Engine School which seems pretty damn cinsistent with how both builders have ALWAYS designated locomotives.