# What do the letters/numbers mean on the Diesel engines?



## strongestfaith1 (Apr 17, 2011)

I'm just getting started in HO scale trains and need to know what the letters and numbers signify when purchasing, ie. B23; GP40; etc.?


----------



## Bangor and Aroostook (Jan 23, 2011)

I've been using Wikipedia a lot. Do a search for b23 diesel wiki or gp40 diesel wiki or any other type engine you want to research and you'll get hours of reading entertainment. Included are specs, number of units built, the rail lines the original units were sold to and more. Great informational resource. 

Oh, and FYI while I'm here, it was Wikipedia that told me that a BL2 was designated as a Branch Line engine, nicknamed "The Ugly Duckling" and was the predecessor of the GP7, etc., units.


----------



## Zeus-cat (Feb 5, 2011)

They are model numbers of the real locomotives. The GP40 is the EMD GP40, a 4-axle diesel-electric locomotive built by General Motors. 

Bangor and Aroostook gave good advice; use the net to do a bunch of research if you need to know all of the details.


----------



## tjcruiser (Jan 10, 2010)

Strong,

I raised a similar question a while back. A few members offered some very helpful links, per the thread below ...

http://www.modeltrainforum.com/showthread.php?t=5252

Cheers,

TJ


----------



## Massey (Apr 16, 2011)

To drop some basics here each manufacturer has thier own system but they are similar. GE's number relates to the HP of the prime mover, EMD relates to the Locomotive Series.

EMD uses a prefix to deisgnate the loco's job and axle setup GP= General Purpose 4 axle, SD= Special Duty 6 Axle. GE uses the older B and C designation "B" for 2 axle trucks and "C" for 3 axle trucks. 

At the end of the designation is specific model info such as wide cab, or AC traction or variant info. Here is an example.

SD70= Special Duty, (6 axle) 70 Series Locomotive, DC Traction motors
SD70M= Special Duty, (6 axle) 70 Series Locomotive, DC Traction motors, Wide Cab("M")
SD70MAC= Special Duty, (6 axle) 70 Series Locomotive, AC Traction motors, Wide Cab("M")
SD70ACe= Special Duty, (6 axle) 70 Series Locomotive, AC Traction motors, Meets EPA regulations, (No cab designation since the wide cab is the only one available on this model)
SD70M-2= Special Duty, (6 axle) 70 Series Locomotive, DC Traction motors, Wide Cab("M") Second Version, (Looks like the SD70ACe but with DC traction motors.

GE looks like this 
8-40C= Series 8 (or Dash 8), 4000 HP Prime Mover, "C" Trucks (3 axle)
8-40CW= Series 8 (or Dash 8), 4000 HP Prime Mover, "C" Trucks (3 axle), Wide Cab
8-40B= Series 8 (or Dash 8), 4000 HP Prime Mover, "B" Trucks (2 axle)(Amtrack used these engines)
9-44CW= Series 9 (or Dash 9), 4400 HP Prime Mover, "C" Trucks (3 axle), Wide Cab

Hope this helps you understand the engine designations

Massey


----------



## norgale (Apr 4, 2011)

Massey you seem to know your engines pretty well. I have to study up on this stuff as the letters and numbers confuse me too. Good info there. Thanks for posting it. Pete


----------

