Dash 9?

[Anonymous]

SD also means Swithcing Duty

[edblysard]

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

[M636C]

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

The "special duty" referred to the fact that at the time of introduction of that model, six driven axles were only needed for operation on steep grades. With current designs, six motors are normal, and the equivalent "GP" units have not been built since the GP60.

When wide nose cabs were introduced EMD used the suffix "M", and when they introduced inverter controlled AC motors, they used "AC" to indicate that.

Thus an SD70MAC is a six motor (SD) 4000HP (70 model) wide nose cab (M) with inverter controlled AC motors (AC) unit.

I'll bet that a lot of other forum readers didn't know that either!

Peter

[Willy2]

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