As silly as this question may sound (laugh if you must), I don’t really know the answer. Okay, when I see a SD70MAC or a GP38 what exactly do these numbers stand for? Are they simply a model number or do they have anything to do with horse power or… well… what exaclty do they mean?
The GP38, or the 38, was a subset of the 40 series. The 38 has a 16 cylinder, 2-stroke 645 engine with Roots blowers, producing 2000 HP (16-645E). The 39 has a 12-cylinder turbocharged 645, producing 2200 HP (I might be a little off on that, 12-645E3). The 40 has a 16-cylinder, turbocharged 645 engine producing 3000 HP (16-645E3). The SD45 had a 20-cylinder 20-645E3 engine producing 3600 HP.
Dawo - the -2 designation on any of the above units denotes an updated design with modular electronics/electrics and other enhancements. The original 40 series went into production in 1966, the Dawo is any made from 1972 onward to the end of the 40 series in 1986-87 (some GP38-2s for Canadian Pacific, which were the last of the 40 series made).
The 50 series has a 3500 HP 16-645F3 engine, the 49 was the 12-cylinder version (I think Alaska Railroad was the only railroad with these)- there was no 48. These have the da***wo electric treatment.
The 60 series has a new engine, a 3800 HP 16-710G3 engine. The 59 is the 12-cylinder, 3000HP variant. It is also the first microprocessor controlled locomotive on the market (1984). The microprocessor control on these was available as a retrofit upgrade for the 40-series units, which when rebuilt were given the da***hree designation (SD40-3).
The 70 series has a 4000 HP 16-710G3B engine, and 3-axle radial trucks (6 axles, no 4-axle GPs).
The SD75I was a 4300 HP 16-710G3C powered locomotive with an isolated wide cab (for comfort).
The SD80 was basically an SD90, but with a 20-cylinder 20-710G3C producing 5000 HP.
The SD90 was equipped with a new, buggy 4-stroke 16V265H engine producing 6000 HP. Many SD90s were built before the 4-stroke engine was ready to see daylight - these were equipped with the 4300HP 16-710G3C engine to be changed to the 16V265H later. Due to the problems encountered with the aforementioned H engine, most of these retained their 2-stroke 710 engines. These ar
The numbers of EMD models are just numbers, no relation to HP or anything, Although the trend for higher HP means that the higher the number the higher the HP.
The numbers of GE models are generally hundreds of horsepower. The same with ALCo towards the end.
OK, I just gave back the book I’d borrowed about “vintage” Diesel power, but IIRC, between that and some other sources, even early EMD products started out with some semblance of correlation between the model and horsepower. At one point the “F” in the F series and the “E” in the E series actually stood for the horsepower (F for 1,500 and E for 1,800?). IIRC, the GP30 totally blew that away, as it wasn’t 3,000 horsepower, but rather had 30 “features”. As has been noted, there has been no correlation since.
Most of the defunct manufacturers included the horsepower in their model numbers.
Wow, thank you so much. I think I am going to print this to keep it handy. That is some excellent info. Thank again.
Including GE. Except they’re still around. [}:)]
EMD occasionally toyed with a horsepower-based designation system, including the NW (Ninehundred hp), FT (Fourteenhundred hp, though it was actually 1350hp), and E (Eighteenhundred hp), among others. Later, they had the SD24 (2400 hp) and GP18 (1800hp). As mentioned above, they departed from the HP-based numbers because GE had the U25B and Alco had the C425, while EMD was developing the GP22 (2250hp). Instead, they made the GP22 the GP30 to make their model sound more impressive, though it had less power than the two competing models.
Marketing, ain’t it great! I always thought the GP30 looked best of that generation, though…
Isn’t that the truth! I’ve always wished the 30 series had been as popular as the 40 series. Alas! the 30 and 35 were starting to pu***he envelope of the 567, whereas the 645 was just beginning its life in the 40 series.
BTW, Silicon, great post!
Yeah, just imagine an SD40 with the 30’s styling… now that would have been cool, with all those units roaming the country! EMD probably would have changed the styling for the Dash 2s though, I imagine it was a little more expensive to produce that nifty flaring and sculpted cab, which is why it was only on the GP30…