what is up with locomotive classification?

[NorthWest]

I think I note some scarred MILW paint on that MP15AC. A bandit?

I'm not sure, but toilets may have been optional.

The GP15 and MP15 families were built concurrently. The GP15s were intended to replace worn GP7s and GP9s, with maximum trade in parts to lower costs (although the GP15AC and GP15T didn't use the generator).

[M636C]

Paul of Covington

    A practice that I always thought was kind of odd was that of using letters to denote numbers.

UP uses "FEF" to denote Four-Eight-Four.

EMD used "F" to denote Fourteen hundred horsepower and "E" for Eighteen hundred horsepower.

While "SW" came to mean switcher, I think I remember reading that it was originally Six hundred horsepower, Welded frame, as opposed to "SC" which had a cast frame.

It isn't often I find a thread that I commented on seven years ago but only one page back.....

EMD made extensive use of letters representing numbers....

Not everyone agrees with "F" for "Fourteen" (but I do...)

Others, in arithmetical order were:

S for 600 HP

N for 900 HP

T for 1200 HP

E for 1800 HP

Most of the pre 1941 model codes used this system

TR for Transfer was an exception.

It is fairly clear that FT stood for Fourteen Hundred Horsepower Twin Unit, since the model FS  (1400 HP Single Unit) was used for the Santa Fe units that had couplers rather than drawbars.

M636C

[Richard_S]

Mike, Are you sure you don't have a MP15T? Count the number of cylinders on the diesel engine. If it's a eight cylinder diesel engine it's a MP15T If this is true, then I can understand how they used the extra space between the Main Generator and the cab for a toilet room. Good old pumper toilets, got to love them. Everyone is getting rid of the Evac's because of the price, plus the extra space needed for the holding tank and fresh water tank. 

I can assure you on the railroad I work for, If I open one of the carbody doors just outside the cab, I gain access to either the slip rings on the MP15AC Main Alternator or the commutator brushes on the MP15DC Main Generator.  

[WSOR 3801]

MP15ACs do have toilets.  First door in the hood outside the cab door.  Somewhat cramped, and quite breezy, but it is there. 

Most GP15s have a DC main gen, rebuilt from the one traded in on the core GP7-9.  My carrier passed on buying secondhand GP15s due to this fact, instead getting MP15ACs, with the attendant cramped cabs, poor ride, and small fuel tanks, which limit operations.  Can't leave them at outlying points for long periods, run out of fuel.  Sending a fuel truck costs $0.50 a gallon more than refueling at the fuel racks. 

From some of the things I have read, a GP38-2 was already less expensive than a MP15AC. 

[Richard_S]

The MP15AC only has a Main Alternator, it still has DC traction motors. The MP15DC still had the Main Generator. Because of the short length of the hood and the placement of the Main Generator on the MP15DC, the brushes in the Main Generator were very difficult to service.

To answer another question, Switchers, Yard Units, Goats, Shifters, (SW9, SW1001, SW1200, SW1500, MP15DC, MP15AC) do not have toilets. Originally GP15's were meant to be the replacements for MP15's. You'd trade in your MP15, EMD would remove the prime mover, Main Gen, Aux Gen and traction motors and place those components into the GP15 and you'd end up with a fairly new hood unit for a lower cost than purchasing a new GP38-2.  Also of note, the noise level inside the cab of a switcher was higher than the noise level inside the cab of a GP15. 

[DSchmitt]

Paul of Covington

While "SW" came to mean switcher, I think I remember reading that it was originally Six hundred horsepower, Welded frame, as opposed to "SC" which had a cast frame.

I believe you are correct. There were also the N series switchers "NW" and "NC". The early ones were Nine hundere horsepower.

[Paul of Covington]

    A practice that I always thought was kind of odd was that of using letters to denote numbers.

UP uses "FEF" to denote Four-Eight-Four.

EMD used "F" to denote Fourteen hundred horsepower and "E" for Eighteen hundred horsepower.

While "SW" came to mean switcher, I think I remember reading that it was originally Six hundred horsepower, Welded frame, as opposed to "SC" which had a cast frame.

[CSSHEGEWISCH]

The Whyte system wasn't always consistent, either.  Consider the B&O and PRR duplex-drive locomotives, which were rigid-framed.  Their Whyte system designations (4-4-4-4, 4-6-4-4 and 4-4-6-4) implied that they were articulated locomotives when they were really divided-drive 4-8-4's and 4-10-4's.

[ACY Tom]

Believe t or not, it was both simpler and more complicated in steam days. Most folks use the Whyte classification system in conversation, which made it simpler. But each railroad had its own unique classification system, which was usually Alpha-numeric. One of the biggest exceptions was the Santa Fe, which used locomotive number series. When similar engines (2900's and 3776's, for example) were put into dissimilar number series, the result could be confusing to outlanders. I believe the Katy used a system that involved a "%" sign, and other roads may have done the same. While most roads did use an Alpha-numeric system, there was no agreement as to what letter should designate a particular wheel arrangement. Mikados on the PRR were class L; B&O class Q; NYC and NKP class H; Erie class N; Southern class M; L&N class J; NP class W; GN class O; etc. For a time, a small letter "s" designated a superheater on the PRR and Southern, but the two roads disagreed on where to place the s, before or after the class number. The PRR always had to be different on general principles, so they refused to use hyphens. I've barely scratched the surface.

[puffy]

Traditionally, the difference between a switcher and a road switcher was the short hood end that contained a steam generator and AAR trucks that allowed higher speed operation. The road switcher (which has come to be called a hood unit unit) differed from the cab unit (regular road engine) in that the crew could see down the side of the locomotive both ways without putting their heads outside. From this point on things began to get blurred. I remember discovering that 1186, an ex-B&M ALCO-GE S-3, had the remains of an ATC box out front of the engineer's side of the cab on the running board as a result of being used in passenger service on the Fitchburg Division (must have been cold passenger cars in the winter!)

[THayman]

What is the difference between a SW switcher and a Road Switcher?

What is the difference between a road switcher and a regular road engine?

Switchers are not designed for road operation. They have simpler trucks, sometimes smaller traction motors, and generally have smaller diesel engines of 600 to 1500 HP. Generally, they have a cab at one end, with no short hood. They also generally have smaller fuel tanks.

So an MP15DC is a switcher, with a cab at one end. The GP15 with exactly the same equipment (but a short hood) is a small road switcher.

The name road switcher dates from the time that road locomotives were cab units. The then new hood units could be used for both switching and road traffic. Thus the name road switcher was used to indicate this. All road locomotive built recently are road switchers (except for a few passenger locomotives, which are still cab units).

M636C

and mordern passenger engines are not true cab units.......cab units have trusses built into the sides that support the unit.....hood units have a heavy frame the unit is supported on.....the F45...FP40 are realy just hood units with a "cowling" covering the innerds......not realy sure about the P42......looks like some kinda unibody type.....lil help with that one

The P42 is a monocoque "frameless" design. The body is one piece which is self supporting, without a central frame. It is not like the cowl or hood units in that regard.

 

[CSSHEGEWISCH]

The line between switchers and road switchers has become increasingly blurred.  SW1000's and SW1500's had the option of Flexicoil trucks, which rode better at speed, and all of the various incarnations of the MP15 were on road trucks.  The Alco C415 had a similar option.  At any rate, the line was easier to draw when switchers had end cabs and lower hoods over the engines.

The carbodies on the products of MPI, Railpower and NRE aren't helping, either.  They continue to have the lower hood over the engine(s) but have moved the cab away from the end.

[snagletooth]

What is the difference between a SW switcher and a Road Switcher?

What is the difference between a road switcher and a regular road engine?

Switchers are not designed for road operation. They have simpler trucks, sometimes smaller traction motors, and generally have smaller diesel engines of 600 to 1500 HP. Generally, they have a cab at one end, with no short hood. They also generally have smaller fuel tanks.

So an MP15DC is a switcher, with a cab at one end. The GP15 with exactly the same equipment (but a short hood) is a small road switcher.

The name road switcher dates from the time that road locomotives were cab units. The then new hood units could be used for both switching and road traffic. Thus the name road switcher was used to indicate this. All road locomotive built recently are road switchers (except for a few passenger locomotives, which are still cab units).

M636C

 

 but a MP15ac with bloomberg trucks, dynamic brakes and large fuel tank MU hook ups........is it a switcher or a smaller road switcher??????

MP15AC stands for Multi-Purpose, 1500HP, Alternating Current equipt. Multipurpose meaning it's designed as a switcher, but with added capacities so it can be used as a light road switcher.

[WSOR 3801]

The Amtrak Genesis units are a "unibody".  The sides provide some of the framing, like the old Es and Fs. 

MP15ACs have road trucks, some might have had dynamic brakes, but I don't think they had a toilet.  If they did, it must be crammed in there somewhere, not nice to use.  They also didn't ride so good at road speeds, kinda bouncy.  SW1500s were available with Flexicoil trucks, allowed them to go 65 mph. That must have been a heckuva ride.

[J. Edgar]

What is the difference between a SW switcher and a Road Switcher?

What is the difference between a road switcher and a regular road engine?

Switchers are not designed for road operation. They have simpler trucks, sometimes smaller traction motors, and generally have smaller diesel engines of 600 to 1500 HP. Generally, they have a cab at one end, with no short hood. They also generally have smaller fuel tanks.

So an MP15DC is a switcher, with a cab at one end. The GP15 with exactly the same equipment (but a short hood) is a small road switcher.

The name road switcher dates from the time that road locomotives were cab units. The then new hood units could be used for both switching and road traffic. Thus the name road switcher was used to indicate this. All road locomotive built recently are road switchers (except for a few passenger locomotives, which are still cab units).

M636C

and mordern passenger engines are not true cab units.......cab units have trusses built into the sides that support the unit.....hood units have a heavy frame the unit is supported on.....the F45...FP40 are realy just hood units with a "cowling" covering the innerds......not realy sure about the P42......looks like some kinda unibody type.....lil help with that one

[J. Edgar]

What is the difference between a SW switcher and a Road Switcher?

What is the difference between a road switcher and a regular road engine?

Switchers are not designed for road operation. They have simpler trucks, sometimes smaller traction motors, and generally have smaller diesel engines of 600 to 1500 HP. Generally, they have a cab at one end, with no short hood. They also generally have smaller fuel tanks.

So an MP15DC is a switcher, with a cab at one end. The GP15 with exactly the same equipment (but a short hood) is a small road switcher.

The name road switcher dates from the time that road locomotives were cab units. The then new hood units could be used for both switching and road traffic. Thus the name road switcher was used to indicate this. All road locomotive built recently are road switchers (except for a few passenger locomotives, which are still cab units).

M636C

 

 but a MP15ac with bloomberg trucks, dynamic brakes and large fuel tank MU hook ups........is it a switcher or a smaller road switcher??????

[M636C]

What is the difference between a SW switcher and a Road Switcher?

What is the difference between a road switcher and a regular road engine?

Switchers are not designed for road operation. They have simpler trucks, sometimes smaller traction motors, and generally have smaller diesel engines of 600 to 1500 HP. Generally, they have a cab at one end, with no short hood. They also generally have smaller fuel tanks.

So an MP15DC is a switcher, with a cab at one end. The GP15 with exactly the same equipment (but a short hood) is a small road switcher.

The name road switcher dates from the time that road locomotives were cab units. The then new hood units could be used for both switching and road traffic. Thus the name road switcher was used to indicate this. All road locomotive built recently are road switchers (except for a few passenger locomotives, which are still cab units).

M636C

[spikejones52002]

What is the differance between a SW switcher and a Road Switcher?

What is the differance between a road switcher and a regular road engine?

[Mimbrogno]

Baldwin names are the most straight forward, and they are also the longest. Believe it or not, but DRS 4-4-1000 is not the full designation of the locomotive. The full and proper designation for that class of locomotive is DRS 4-4-1000/1 SC#, where D (diesel) R (road) S (switcher) 4 (4 axles) - 4 (four powered) - 1000 (Hp per engine) /1 (x1 engine) SC (supercharged) # (denotes the serial number of the unit in the class). 

 Because of the length of the names, making them so hard to pronounce, BLH created shorthand designations for new locomotive classes from 1950 onward. These are the more familiar AS-616, RS-12, and the like. The nicknames have occasionally been applied to pre-1950 locomotives also, resulting in some interesting ones like RP-415, S-6, RT-20, RP-830, KO-1000, and the more common VO-660 and VO-1000. But just because they used the shorthand names doesn't mean they did away with the proper designations either. For instance, the full designation for the AS-616 and RF-16 is DRS 6-6-1600/1 SC and DR 4-4-1600/1 SC, respectivly. So then, take a guess at what a DR 4-2-1000/1SC was.

 Those aren't the only designations Baldwin used for it's diesels either. In the beginning, Baldwin applied the White system to them, as in the case of the four 0-4-4-0 1000/1 OE, the 0-6-6-0 1000/1 OE, the 4-8-8-4 750/8 OE, and the seven 0-6-6-0 1000/2 DE locomotives. The last one actully happened to include 3 very different locomotive types, three A-1-A streamlined passenger units (A Baldwin version of an E unit, if you will), three of what would later become the six CNJ double cab commuter diesels, and the prototype C-C centercab Transfer locomotive. The confusion that resulted from this led Baldwin to change it's designation system to the DRS format in 1946-47.

-Matthew Imbrogno
Mechanical Volenteer, Arizona Railway Museum
www.azrymuseum.org

 

[TomDiehl]

hi,

i have noticed locomotives with names like C424, SD40-2, RS10, DRS-4-4-1000, GP9, ES44AC, and 44-tonner. i'm just wondering how do people name locomotives? is it coded messaging? what is it

Actually, the Baldwin designations, like the DRS-4-4-1000 are the most straight-forward:

DRS = Diesel Road Switcher

4-4 = 4 axles, 4 powered

1000 = 1000 horsepower

[WSOR 3801]

Fairbanks Morse:

H- hood unit

C- cab unit -F - freight, P- passenger

First 2 numbers - horsepower in hundreds

Third number and fourth numbers - number of axles, and number of powered axles 

H10-44 - 1000 hp switcher

H24-66 - 2400 hp, 6 axle Train Master.

CFA16-4 - 1600 hp cab unit C-liner (B-unit would be CFB-16)  Some passenger C-liners had 5 axles.

That is the basics.  Some models were a bit different. 

 

[nbrodar]

*Note - not all codes are used concurrently.* 

EMD:
F - cab unit - 4 axle
E - cab unit - two A1A trucks
B - cabless booster unit

SW - end cab switcher replaced by MP
GP - General Purpose - 4 axle
SD - Special Duty - 6 axle
# - model number
-2 following the number indicates Dash 2 modular electronics
P - passenger unit
H - equipped with Head End Power for passenger cars
M - wide cab
AC - Alternating Current Drive

GE:
U - Universal series (aka U-Boat)
- 7 - Dash 7 equipment
- 8 - Dash 8 equipment
- 9 - Dash 9 equipment
ES - Evolution Series equipment
# - indicates horsepower in hundreds
B - 4 axle
C - 6 axle
W - wide cab
AC - Alternating Current Drive
DC - Direct Current Drive
H - Head End Power equipped

Alco:
FA - Cab unit - 4 axle
FB - cabless booster unit - 4 axle
PA - cab unit - 6 axle
PB - cabless booster unit - 6 axle
S - end cab switcher
RS - road switcher - 4 axle
RSC - road switcher - two A1A trucks - IIRC
RSD - road switcher - 6 axle - IIRC
# - model number

C - Century Series
1st # - number of axles
2nd & 3rd # - horsepower in hundreds

I'm not all that familiar with the Baldwin and Fairbanks Morse classifications.

Nick

[sfrailfan]

Yes, there is a logic to this. The differences come from different producers.

GP, SD and SW are EMD designations.
gp stands for general purpose, (emd hasn't made one since the gp 60, there are other new 4 axels but.....)
sd stands for special duty
and sw stands for switcher.

GE prior to the C30 -7 used codes like U23B and U23C. The B stood for 4 axel and the C stood for 6 axel. The 30 I believe stood for the engine horse power like in the AC4400 (4400 HP) but I don't remember exactly the method of GE classification here. Someone will yell at me soon for that.

It goes on with the Alcos ect. you get the idea. This can be looked up to get all the facts or someone who knows of the top of their head will let you know soon enough.

[CPRail modeler]

hi,

i have noticed locomotives with names like C424, SD40-2, RS10, DRS-4-4-1000, GP9, ES44AC, and 44-tonner. i'm just wondering how do people name locomotives? is it coded messaging? what is it