Locomotive nomenclature

[pathe]

Most posts are on track. My Dad worked at EMD from 1938-1979 retiring as Director of Production. College summers 1962-1964, I worked there, and I still have some large blueprints a buddy made for me of the original locos.

I beleive that F means Fouteen hundred horsepower (1400) the FT's were 1,350 (why not round up) , E means Eighteen (1800 HP) -- the first E units had two 900 HP prime moers. S = Six (600 HP), N = Nine (900 HP), C = Cast, W = Welded (frames on switchers). GP (General Purpose) and SD (Special Duty) used for non-hood 4 and 6 axle locos respectively. BL = Branch Line (EMD didn't sell many)

One of those summers, a bunch of us went over to watch the fist DD frame being flipped over on the erection line. Frames were built upide down to add all the tanks, wiring and piping.  It was welded together with a 8 inch or so upside bow. When the two 16-cylinder diesels and two geneators, etc. were loaded on top, the frame settled down to about a quarter inch of being flat. This was iin the day of slide rule calculations.

[BentnoseWillie]

I've altered my document to include more correct definitions of F, FP and SW, added SC, and fixed the FM numbers. Whoops [:I]

For F/FP I'm changing it to read thus:

QUOTE:
F = 4 or 6-axle cowl-body freight or passenger locomotive. Can include steam generator or HEP equipment (see PH suffix below).
FP = 4 or 6-axle cowl-body passenger locomotive with steam generator. Extended carbody on 4-axle version.

EMD's S did indeed stand for "Six" and N for "Nine" (hundred HP), and W was for Welded frame. However, as fas as I know this only extended to the S and N series units.

In the interest of clarity I won't edit the above post; that way later readers can see the boo-boos that your replies pertain to. Next time I post the document it'll include the changes. This is a "living" text file that I maintain, and I appreciate all feedback and corrections.

[lionelsoni]

Will is correct in that the last two digits of the Fairbanks-Morse designation indicate the numbers of powered and idler axles, not the numbers of wheels on the trucks, as I suggested. However, I think he has them reversed, as in the case of the H-12-46.

I stand by my assertion that the early EMD letters indicated nominal horsepower, not "freight", "passenger", "switcher". Although later "SW" locomotives were switchers, with the horsepower rating moved to the numerical field, the letters originally designated a 600-horsepower unit with a welded, as opposed to cast, frame.

[DSchmitt]

"F = 4-axle cowl-body freight locomotive.
FP = 4-axle cowl-body passenger locomotive (equipped with steam generator)."

The identifying difference between an Electro Motive F and an Electro Motive FP was not the steam grenerator. All FP's had steam generators, but although most F's did not have steam generators they could be equipped with a steam generator too. The FP is about 3 feet longer longer than the F.

[BentnoseWillie]

================
Diesel Greek 101
================
Will Lawrence
Revision of July 2005

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Chapter 1:
Electro-Motive Division / GMLG / Electro-Motive Diesel
------------------------------------------------------

Format: xxyy

xx: Model Designation

GP = 4-axle Road Switcher.
F = 4-axle cowl-body freight locomotive.
FP = 4-axle cowl-body passenger locomotive (equipped with steam generator).
SW = 4-axle switcher.
TR = 4-axle switcher with permanently-coupled 4-axle booster.
SD = 6-axle Road Switcher.
SDP = 4-axle Road Switcher equipped with steam generator.
DD = 8-axle freight locomotive with D trucks and dual prime movers & generators.
E = 6-axle passenger locomotive with A1A trucks and dual prime movers & generators.

yy: Series Number (7,9,18,40, etc. - no direct relation to horsepower)

Common Suffixes:
A = Cowl-body unit equipped with cab (e.g. F7A)
Post-1985: Cowl-body unit with next-generation prime mover (e.g. SD50AF)
B = Cabless booster (e.g. GP60B)
W = Safety Cab (CN 4-windshield design)
M = Safety Cab (EMD 4-, 3- or 2-windshield designs)
I = "Whispercab" option (vibration-isolated cab), later included in M cab design.
F = Full-cowl carbody (SDP40F, SD50F, SD60F, SD40-2F)
AC = Pre-1990: Alternating-current generation with DC traction motors. (e.g. GP38AC, MP15AC)
Post-1990: AC generation AND traction. (e.g. SD70MAC)
-2 = Mid-70's improvements to prior models including modular electrical cabinet and AC
generation (still using DC traction). (e.g. SD45-2, GP40-2, GP38-2)
-1 = Mid-70's locomotive built without "Dash 2" improvements. (e.g. GP15-1)
-3 = Pre "Dash 2" unit subsequently rebuilt with modern electrical equipment.
DC = Unit built with DC generation and traction after introduction of "Dash-2" line
(e.g. MP15DC)
PH = Equipped with generation capacity to supply "head-end" power to electrically
heated/cooled passenger cars. (e.g. F40PH, F59PH)
C = 3-axle trucks with 3 traction motors (F40C)
X = unit, with experimental variation from production specifications (e.g. GP40X)
e = Meets "Tier 2" emissions standards (e.g. SD70ACe)

----------------
Chapter 2:
General Electric
(Pre - 1979)
----------------

Format: Uxxy

U: "Universal Series"

xx: Horsepower (x 100)

y: Axles (all powered):
B = 4 axles
C = 6 axles
D = 8 axles

----------------
Chapter 3:
General Electric
(Post - 1979)
----------------

Format:

xyy-z
Or
"Dash z yyx"

x: Locomotive configuration
B = 4 axle roadswitcher, all axles powered
C = 6 axle roadswitcher, all axles powered
P = Passenger unit, all axles powered (used only on first format above)

yy: Horsepower (x 100)

z: Series number (7, 8, or 9)

Suffixes:
M = Full-cowl carbody (C40-8M for CN, BC Rail, QNS&L)
W = Safety Cab (GE or CN Design)
AC = Alternating-Current generation and traction.


-------------------------------------------------------
Chapter 4:
American Locomotive Company / Montreal Locomotive Works
Pre-1960
-------------------------------------------------------

xx-yy

XX: Locomotive Type

S = 4-axle switcher
RS = 4-axle road switcher
RSD = 6-axle road switcher, all powered
RSC = 6-axle road switcher, 4 powered
FA = 4-axle cowl-body freight Locomotive with Cab
FB = 4-axle cowl-body freight booster without Cab
FPA = 4-axle cowl-body passenger locomotive with Cab
FPB = 4-axle cowl-body passenger booster without Cab
PA = 6-axle cowl-body passenger locomotive with Cab
PB = 6-axle cowl-body passenger booster without Cab

yy: Series Number

Example: RS-1 = 4-axle road switcher, series 1

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Chapter 5:
American Locomotive Company / Montreal Locomotive Works
1960-1969:
-------------------------------------------------------

Format: Cxyy

C - "Century Series"

x - Number of axles (all powered)

yy - Horsepower (x 100)

Suffix:
M: Montreal Locomotive Works variant.

Example: C630M: Century series, 6 axles, 3000HP, MLW variant

-------------------------
Chapter 6
Montreal Locomotive Works
Post-1969:
-------------------------

Format: Mxyy

M - "M-Line"
(Developments in century series produced by MLW after Alco closed in 1969)

x - Number of axles (all powered)

yy - Horsepower (x 100)

Example:
M636 = M-Line, 6 axles, 3600 HP

----------------------------------
Chapter 7:
Bombardier (North American Market)
----------------------------------

Format: HRXYY

HR - "High Reliability" Series
(Locomotive series developed by MLW under Bombardier ownership)

x - Number of axles (all powered)

yy - prime mover configuration

Examples:
HR412 = High Reliability Series, 4 axles, 2000 HP prime mover
HR616 = High Reliability Series, 6 axles, 3600 HP prime mover

----------------
Chapter 8:
Fairbanks-Morse:
----------------

Format: x-yy-zz

x: Locomotive series
CPA = Cowl-Body passenger Locomotive with Cab
CPB = Cowl-Body passenger booster without Cab
CFA = Cowl-Body freight Locomotive with Cab
CFA = Cowl-Body freight booster without Cab
H = Hood-body road switcher

yy: Horsepower (x 100)

zz: Axle count and configuration

4 = 4 axles, all powered
5 = 5-axles, 4 powered
66 = 6 axles, all powered
64 = 6 axles, 4 powered
44 = 4 axles, all powered

Examples:
CPA-16-5 = Cowl-Body passenger Locomotive with Cab, 1600HP, 5 axles (4 powered)
H-24-66 = Hood-body road switcher, 2400HP, 6 axles (all powered)

[Anonymous]

Many of the early diesel's used a truss bridge type of construction where there was no "frame". The locomotive was made up of stamped steel channels aranged in a truss fashion and this was then covered with an outer skin. The EMD F's, E's and Alco PA's were built in this fashion. These were called CAB units. The next series of engines went with a built up steel frame that had a light weight non structural cover and these are refered to as HOOD units. A few railroads requested that their hood units have full width hoods that made them look like CABS (Amtrack FP-45's and FP-40's, CNN and VIA and some SanatFe units). This arrangement was done to allow crew acccess to the engine compartment while still providing cover from bad weather or other intruders. The hood was still just a covering and had little or no structural function. GE has sort of gone back to the CAB design with the Genesis semi-monocoque design. In t his case the engine body is a structural (load bearing) element of the loco.

Pictures of a PA-1 undergoing restoration:

http://www.nkp190.com/scans/Albany/%7Emax0021.jpg

Home page of the restoration project:

http://www.nkp190.com/index.shtml

A's and B's.

CAB style bodies with a control station are A units. Units without controls are called B's (Booster). One of the selling points of early diesel electric locomotives was the ability to connect multilpe units to make a more powerful head end without use of additional crews. The engines were electrically and/or electro-pnuematically connected into consists that were designated by their arrangement. A-A, A-B, A-B-A, A-B-B-A. To faciltate turna around times a consist would often have A units at the ends of the consist facing opposite directions. Crew can get set some switches in the CAB, get down and walk back to the trailing and an now it becomes the lead unit. There are a few B type hoods that were made for for the same reason. Most early hood units could run in either direction but most had a designated "front", usually the long end for protection purposes.

Other letters used in diesel designations:

AC (Alternating Current) for AC traction motors
W (wide, usually associcated with full width operators cabin)
MAC (Micropocessor AC control)

SD70MAC (Special Duty (aka C style truck), 70 Series, Micropocessor controlled AC motors)

AC4400CW AC traction, 4400 hp, wide cab

[lionelsoni]

Early EMD Diesels often were named for their power rating in hundreds of horsepower, using multiples of 300 horsepower and the initial of the number. So S meant 600, N 900, T 1200, F 1500, and E 1800. As new models in a series came out, the power crept higher, but the designation stayed the same. For example, the NW2 had 1000 horsepower, not 900. (The W stood for "welded frame".) The SW2, whoxe name Lionel at first erroneously gave to their NW2, would have been a smaller, 600-horsepower locomotive, had it existed. There is much disagreement about where the FT name came from. I believe it indicated an engine between F and T, 1350 horsepower being the locomotive's rating.

Some locomotives were named for their wheel arrangements. EMD's Centennial was notable for having 4-axle trucks, which are acknowledged in its name, DDA40X. Fairbanks-Morse used a letter for the body style, then the horspower in hundreds, then the numbers of wheels on the trucks. So the Train Master was an H-24-66, a hood style 2400-horsepower locomotive with two 6-wheel trucks.

The GG1 was named that because it had the wheel arrangement of two ten-wheelers, back-to-back; and the Pennsylvania's prefix for a ten-wheeler was "G".

There are two Kalmback books that you should get: "Diesel-Locomotives: The First 50 Years" and "The Contemporary Diesel Spotter's Guide", both by Louis A. Marre.

[csxt30]

Good info there chuckn ! I can only add that I believe the SD stands for Special duty, & there was a DD, like in the DD-40, that stands for double duty. Also, there used to be little booklets out that were called Diesel spotter books. They had pictures & lots of info on the diesels.
Thanks, John

[Anonymous]

http://www.steamlocomotive.com

GG-1 is in there as an honorary steam locomotive.

Diesel nomenclature was more dependant on the builder or ocassionally the owners whims/needs. They often contain some type of desigantion of axle arrangement with a bit of a cary over from their predecessors (steam/electric). Powered axles were designated as A, B, C, D for single axle, double axle, tripple, quad. A numeric indication in a truck arrangment would indicated a non-powered axle. Example, two powered axles on a truck are a "B". An A-1A truck (common on early passenger diesels) was a powered axle with a non powered axle and then another powered axle. Even these standard designations were rarely worked into the designation. EMD "GP" loco's had B-B trucks while their "SD" counterparts had C-C's. The GP stood for General Purpose, and the SD for ? GE- used "U" for Univsersal. Original "F" designation in the EMD F units was a nod to the primemovers size.

Most vendors would also try to work in something regarding the horsepower ratings of the prime mover but these might be in "code" on earlier units. Electrics were often handled the same way.

Here is a link to a yard switcher site, still looking for a comprehensive road switcher site. Excellent source of info in diesel locomotives in general is a Kalmbach publication, Diesels, from D to L. This is a compilation of articles originally doen in Trains magazine afew years back.

http://yardlimit.railfan.net/guide/

GE site:

http://www.answers.com/topic/list-of-ge-locomotives

EMD historical info:

http://www.berga.nu/Lennart_T/EMD_History.html

Photo index of EMD loco's:

http://www.railroadforums.com/forum/showthread.php?t=1280

[spankybird]

here is another good one for steam

http://www.virtualrailroader.com/volume_1/American_steam.html

[spankybird]

here is one for steam engines

http://www.nashvillentrak.org/Whyte.html

http://www.thortrains.net/realrai2.htm

http://www.parmahobby.com/trains/engines-steam.htm

Sorry to say, I can't help you with the Diesels. They all look the same to me, if they don't have side rods and a cow catcher.

[cheech]

happy thanksgiving!

does anyone know a source (book, article, website) for the naming convention of locomotives --steam, diesel and electric.

for newbee's like me, it gets confusing to know the difference between and e8 and an e9...

any ideas will be appreciated