Hi everyone,
What do the different names of engines mean? Like, what does Dash 9 mean and do GP and SD mean? What does E-Unit mean?
Thanks for any answers!
Willy
Willy,
There’s a list of explanations in the “Introduction to Railroads” on the Trains website.
But, to start with GE locomotives, from about 1956, were called “Universal”, and the models were prefixed by “U”, starting in the USA with the U25 in 1959 (where 25 stood for 2500 HP). This continued until 1977, when both EMD and GE improved their designs. GE modified their description to read B23-7 where “B” meant two axles per truck (“C” meant three axles), 23 again meant 2300 HP and “-7” (pronounced Dash 7") was the model. The “7” referred to the year, 1977. A friend then with EMD said that “they just used “7” to have a bigger dash number than us”, since EMD had recently introduced improved models with “-2” (dash 2) to indicate the change.
When further improvements were made GE called their units “Dash 8” written as C40-8 for example, and later still they introduced “Dash 9”. With the “Dash 9”, it was decided to change the way the model was written so an example was the Dash9 44CW, where Dash 9 was the model, 44 the power (4400HP) C meant three axle trucks and W meant “wide nose cab”. At this time GE also introduced locomotives with inverter controlled AC traction motors, and the equivalent AC unit was the AC4400CW, where AC was the model, 4400 the power, and CW meant the same as on the DC units. Now their new units (from 2005) are to be ES44AC or ES44DC, where ES means Evolution Series, 44 means 4400HP and AC and DC mean the type of motors. They only plan to build six motor units at this stage.
EMD models used prefix letters that were originally an abbreviation of the engine power, so you had:
E for eighteen hundred horsepower
F for fourteen hundred horsepower
T for twelve hundred horsepower
S for six hundred horsepower
These letters were kept although E units after E-3 were over two thousand horsepower, for example.
GP meant General Purpose
SD meant Special Duty
You forgot to add that the E Units rode on 6 axel trucks, with the center axel an idler, or non motored axel.
The idea was to distribute the weight of the twin diesels and the assorted equipment evenly.
And, under license, Bosie Locomotive is now making a GP15 and GP 20, 1500 hp and 2000 hp.
In reality, they are the MK1500D, using EMD diesels instead of the cat.
Ed
SD also means Swithcing Duty
SD means specail dudty…
GP means genneral perpouse…
they are an EMD desigation
dash 7
dash 8
and dash 9
are GE units…and the dash (which =s -) is for what decade the unit was designed…
a unit with the model number of CW-44-9AC means… 6 axles…(C=6…B=4 on GE modles…)…W means wide body…( wide nose cab) 44 means the hores power of the unit rounded off to the neartest 100ths…and AC means AC traction…on csx they are the units that have the ligtning bolts under the cab windows on the sides…
EMD units that are wide cabs have an M after the model number… (SD70Mac)
csx engineer
The are correct, however, over time, EMD applied different standings for these abbreviations, for example:
F evolved to stand for "F"reight (hence F unit, passenger versions had a P added ex: FP7, which signified "P"assenger)
T evolved to stand for "T"ransfer (used on TR1, TR2, 3, and so on, these were semi-permentaly coupled (drawbar) cow/calf switcher sets intended for transfer service)
S evolved to stand fo "S"witcher (used on all SC and SW switchers, the C stood for "C"ast frame (only very early units) and the W stood for "W"elded frame (SW1 and on)
Let’s not forget the tunnel motors. Southern Pacific and D&RGW had versions of the SD-40 / 45 with special air intake built to run cooler in tunnels and snowsheads, and EMD used a T to designate these- SD40T-2 SD45T-2 .
Your shure that the engines in GP15 and 20 are GM´s?
I had read that GM12V170B15-T1 (GP 15) and GM16V170B20-T1 (GP20) are GM designations for CATERPILLAR engines!
Guys,
Firstly, I have to support Ulrich’s contention regarding the Boise-built units. They all have Cat 3512 (GP15D) or Cat 3516 (GP20D). The Cat 35 series engines have 170mm bore cylinders, and are described as Ulrich indicates above. Perhaps the locomotives sold by EMD have the engines painted grey rather than yellow.
I also understand that the SD45T-2 and SD40T-2 designations were unofficial, and not recognised by EMD who described them simply as SD45-2 and SD40-2 (with modifications) respectively.
There were some variations in EMD model descriptions that were not widely known. FT originally stood for Fourteen Hundred Horsepower Twin Unit, since the prototypes were coupled by drawbars into pairs of A and B units. The first production units, built for Santa Fe, had knuckle couplers throughout, and these were initially described as model FS, for Fourteen Hundred Horsepower Single Units.
In my first posting, I should have indicated that GE initially only built four motor units for domestic USA use, and thus the U25 initially had no suffix letter. Export units always had the suffix, so the big units for Argentina were U18C, and after six motor units were introduced to the US market, they became U25C, and the four motor units became U25B.
I should have mentioned that four motor passenger units were built recently by both GE (P42DC) and EMD (F59PHI).
It is possible that “F” never really stood for “freight”, but just meant a four motor cab unit, since the F40C and F40PH were always dedicated passenger units. Also, many Santa Fe F-3 and F-7 A units were dedicated passenger units, but were not “FP” units because they had no steam generator themselves, relying on steam generators fitted in the B units operated with them. It is possible that the attribution of the meaning “freight” to F units was only by enthusiasts based on the apparent use of most of these units.
Peter
Next time the EMD service rep is down, I will ask him.
Or, next time UP leaves one in the yard, I will go look.
Could have sworn the last time we were testing them for EMD, the rep said they were EMD powered, but then again, I was having too much fun watching him turn green from all the start and stops a flat yard switch motor makes…
I can tell you this much, they are very, very good switch motors, load up fast, kick steady and hard, and stop on a dime.
Ed
If you folks think the EMD and GE model designations are confusing… try ALCO and Montreal Locomotive Works!
Or Baldwin
Wow! Thanks for all of the great answers. All of the different symbols and letters make a lot more sense to me now than they did before!
Willy
Somebody gonna hit Willy2 with a photo quiz on identifying mongrels like the ATSF “Beep”, SF30C & CF-7, PC/CR/ATK "DeWitt Geep"s, CNW/MKT “Buffaloes”, Missouri Pacific GP-16’s, Crandall Cabs, MK-TE 1500’s, CRIP “Christine” DL-109M (just south of Willy @ Baldwin, KS), Mexican SLP Homebuilts and the like?
Where is the “Beep” (ATSF 1460) these days?
While we are on the subject, what is “M” in C-30M.
I saw ex-UP now HLCX 588 today on a CSX line.
Thanks!
What? ALCo designations hard? actually their quite easy. I will post them later.
For Willy2’s benefit:
Oops!..We almost forgot about the “Mongeese”…EMD’s BL-1 & BL2’s…sort of fits in the evolutionary chain between the F’s and the GP’s… only 59 built in the late 40’s
BL = Branch Line (you’d know one if you saw one…slightly unique)[tup][tup]
now somewhat partial to DL-535E’s having had the chance to ride behind them and their GE cousins with an 251 under the hood of either.[8D]
Mudchicken,
I assume you are talking about the White Pass and Yukon. I saw very similar units in Argentina, but the DL-535s were on 5’6" gauge and the shovelnoses (built with Cooper Bessemers, but rebuilt with Argentine built 251s) were on Metre gauge. I haven’t travelled behind either, but did get to travel behind the unique DL-540s (DL-702s with DL-500 trucks), and GR-12s.
Maybe I should start explaining export codes!
Peter
Export codes ???
I wouldn’t mind knowing more about that.
I think you mean C36M. The “M” means MODIFIED.
The HLCX 588 was built as ATSF C30-7 #8015.
All numbers: ATSF 8015 - GECX 8015 - GECX 581 -UP 588 - HLCX 588.
Rebuilt for UP into a C36Ms by Metro-East Industries, East St. Louis, Ill.or VMV Enterprises, Paducah, Ky…
3.750 hp instead of 3.000 hp.