Road Engnine

[YellowHillsCentral]

Okay,
I need to know what the definition of a road engine please. I mean, I know, but I don't know, ya know? --whatever. PLEASE HELP ME!

[the Bach-man]

Dear YHC,
It's a locomotive used on the line, as opposed to a switcher, used in the yards.
Have fun!
the  Bach-man

[Tom Lapointe]

A "road engine" , in railroad lexicon, usually refers to a locomotive used mainly for mainline service - getting a complete train from point "A" to  point "B", with little or no switching operations performed enroute.   A "yard engine" by contrast, is used entirely for switching operations.     Examples of road engines would be larger locomotives like U.P.'s Challenger 4-6-6-4's & 4-8-8-4 Big Boys, N.Y.C.'s 4-6-4 Hudsons & 4-8-4 Niagras, PRR's K4s 4-6-2 Pacifics & 4-8-2 Mountain types in steam; EMD E-units, Alco PA's, most 6-axle high-horsepower hood diesels.  Steam yard engines were typically 0-4-0's, 0-6-0's or 0-8-0's.  In diesels, EMD units carrying the "SW designation (SWitcher) were designed primarily as yard units.                               Tom 

[Kevin Strong]

I have heard on more than one occasion that the "W" in SW stood for "welded," a reference to the construction of the frame. Not being a diesel person, I filed it away as mere trivia, not relevant historical fact.  Perhaps someone will chime in to clarify.

Later,

K

[Tom Lapointe]

I have heard on more than one occasion that the "W" in SW stood for "welded," a reference to the construction of the frame. Not being a diesel person, I filed it away as mere trivia, not relevant historical fact.  Grin Perhaps someone will chime in to clarify.

I won't dispute you on that, Kevin; I'm not a "diesel guy" either!   Would be interesting to find if that's true.

                                                                                                             Tom

[Charlie Mutschler]

The road engine,or road locomotive, is the locomotive assigned to move the train over the road.  One or more helper locomotives may be added to the train to assist it in climbing steep grades.  The helper may be coupled in front of the road locomotive, behind the caboose, between the last car and the caboose (preferred practice with wooden framed cabooses), or into the middle of the train.  At the summit of the climb,the helper(s) are cut out of the train, and the road locomotive handles the train down grade by itself. 

[Cascade Northern]

Here is a LONG list of diesel locomotive classifications:

Diesel Locomotive Builders

ALCO - America Locomotive Company
BBC - Brown Boveri Company, now ABB, Switzerland 
BLH - Baldwin-Lima-Hamilton Corporation
BLW - Baldwin Locomotive Works
Budd - Budd Company 
EMC - Electro Motive Corporation
EMD - Electro Motive Division
EMD - Electro Motive Diesel 
F-M - Fairbanks-Morse
GE - General Electric
GM - General Motors
IS - Ingalls Shipbuilding Company 
KM - Krauss-Maffei  Aktiengesellschaft, Germany 
L-H - Lima-Hamilton
MLW - Montreal Locomotive Works
RailPower - RailPower Technologies Corporation   
SIG - Schweizerische Industrie Gesellschaft, Switzerland 
UA - United Aircraft, Surface Transportation System of Sikorsky Aircraft Division 
WS - Werkspoor N.V. Amsterdam, Netherlands

Model Classification

4S - 4-axles Switcher
A unit - Cab Unit   
AA - Motorcar A-unit
AB - Motorcar B-unit
AC - Alternating Current
AMD - Amtrak Diesel
AS - ?
B - 2-axles
B unit - Cabless Booster Unit
BL - Branch Line
C - Century (Alco)
C - 3-axles (GE)
C - Cummins (EMD)
CFA - Cab unit Freight  A-unit
CFB - Cabless unit Freight B-unit
CPA - Cab unit Passenger  A-unit
CPB - Cabless unit Passenger  B-unit
DD35B - 8-axles (D-D) using SD35 components B-unit
DDA40X - 8-axles (D-D) A-unit using SD40 components
DL - Dual Service
DR - Diesel Road unit
DRS - Diesel Road Switcher
DRS6-4-15 - 6-axles 4 powered 1,500 Horsepower
DS - Diesel Switcher
DT - Diesel Transfer
E - Eighteen-Hundred Horsepower
Erie - Built at the plant in Erie, PA (F-M)
F - Freight
FL - Freight with special third rail electric pick-up
FP - Freight-Passenger
FT - Freight Twenty-seven-Hundred Horsepower
GP - General Purpose
H - Hood unit
H10-44 - Hood unit, Thousand Horsepower 4-axles 4 powered
HH - High Hood
I - Insulated Cab
LTW - Lightweight Train   
M - Montreal-designed
M - North America Wide Cab, DC current   
MAC - North America Wide Cab, AC current
MP - Multipurpose
NC - Nine-Hundred Horsepower, Cast Frame
NW - Nine-Hundred Horsepower, Welded Frame
PH - Elongated Frame, Steam Generator
RAm - Locomotive with speed over 110 km/h (R), train composition with 1. class coach (A), diesel engine (m)
RDC - Rail Diesel Car   
RF16 - Road Freight 1,600 Horsepower
RS - Road Switcher
RSC - Road Switcher 6-axle, 4 powered (A1A)
RSD - Road Switcher 6-axles
S - Switcher
SC - Six-Hundred Horsepower, Cast Frame
SD - Special Duty
SDP - Special Duty Passenger
SW - Six-Hundred Horsepower, Welded Frame
SW - Switcher (after HP increased over 600 HP)
SW1 - Switcher Version 1
SW900 - Switcher 900 Horsepower
TR - Transfer
U - Universal
VO - ? 
W - Wide Cab

And I am sure there are many many many more........