PENNSYRR.COM by Jerry Britton

Shout out to Kaylee Zheng whose clinic was the initial data for this cheat sheet!

EMD Model Designation

Example: SD  70        AC

Unit Type Locomotive Series Improvement Series Options/Modifiers
F = Cowl/Monocogue Unit
SW = Switcher
MP = Multi Purpose Switcher
GP = General Purpose (4 axle)
SD = Special Duty (6 axle)

If last digit is 9, then 12 cylinder prime mover; otherwise 16 cylinder.

Exception: T4 locos are 12 cylinders always

(blank) = base version

-1 = EMD reman. program (late 1960s)

-2 EMD reliability improvement series

A = Special Custom Builds
AC = Alternator or AC Traction
M or W = Wide cab
I = Isolated (vibration reducing wide cab)
L = Lightweight frame
P = Passenger/steam heat
H = Head End Power (HEP)
e = Reduced emissions compliant
-T4 = Tier 4 emissions compliant
IAC = Individual Axle Control
P4 [?] = B1-1B wheel arrangement
X = Experimental


GE Model Designation

Example: Dash9  44 C  W

Locomotive Series Locomotive HO x 100 Wheel Arrangement per Truck Options/Modifiers

U = Universal
P = Passenger
Dash8 = Dash 8 Series
Dash9 = Dash 9 Series
AC = AC Traction Series
ES = Evolation Series
ET = Evolution Series, T4 Compliant

For AC series, full HP is written out, although, conventional 2 digit HP indicator is also used interchangeably  

C = Cowl Unit
H = Head End Power (HEP)
P = Passenger
Q = Extended Crew Cab
W = Wide Cab


Round One:

Roof Line: Clean Roof Line: Congested
Fuel Tank: Angular Fuel Tank: Rounded

Brake Reservoir: Two tanks

Brake Reservoir: Long "Torpedo Tube"
Exhaust stack right before radiator Exhaust stack towards cab
GE ET44AC Right  



Round Two:

Radiator "winged" (except U-boats)

GEVO has mini-radiator in front of main radiator

GEVO T-4 similar to standard GEVO radiator but massive 

Radiator has raised fans:
  • Two large fans - 38 series
  • Three large fans - 40 series
  • Three large fans, angled radiator - 45 series
  • Three large fans, tall radiator screens - 50/60 series
  • Three large fans, tall angled radiator - 70 series
  • Three large fans, chunky angled radiator - 80/90 series
  • Two XL fans, chunky angled radiator - 80/90 series (Ace)
  • Three XL fans, chunky angled radiator - 80/90 series (Ace T-4)

Fan Size: Large = 48"; XL = 54"

more to come



RIght Side View GE DASH9 Right      GE ET44AC Right    
Left Side View GE DASH9 Left      GE ET44AC Left    
Top View GE DASH9 Top      GE ET44AC Top     
Front Quarter View GE DASH9 Front      GE ET44AC Front    
Rear Quarter View GE DASH9 Rear      GE ET44AC Rear