I have a few questions concerning locomotives. First off, my friend’s father would like to know why DC locos are still being bought if AC is better. I heard DCs are cheaper, but ACs are more reliable.
Also, what does the ACe stand for in the SD70ACe and what does the MAC or M stand for SD70M or MAC? Sorry, but never looked into this…[:I].
Also, what is the difference between the C44-9W and the AC4400CW? Is it that the C44-9W is DC and the AC4400CW is AC? Sorry for these stupid questions but I’m kind of a beginner to loco knowledge.
How come UP wants their SD40T-2s called “SD40-2Ts?” Aren’t they the same?
How come the General Electric locos are always talked about being “toasters?” I mean, yeah, they smoke sometimes and shoot flames, but aren’t they still as dependable as an EMD? I’ve seen various numbers of EMDs smoke too.
For example: CSX 766, an SD70MAC, smoking it up, or a patched Conrail (NS) SD40-2 shooting flames…
Is the only difference [this is a REALLY stupid question] between the C40-8 and the B40-8, the axles? Because sometimes the cabs look different.
And also, what the heck is a C41-8? I saw a UP C41-8 and C41-8W before. How are they different from a C40-8 or C40-8W?
Sorry for all the stupid/dumb questions, but I am fairly new to the knowledge of locomotives…
The advantages of AC are realized at low speed lugging. If you are not buying locomotives for low speed service it’s hard to justify the added cost. The difference could be like 1.5 million for a DC unit vs 2.2 million for a AC unit. The inverters used to supply the AC to the traction motors are very expensive. AC motors are brushless and are cheaper to maintain but the inverter maintainance outweighs that saveings.
Here are some domestic EMD letter designations.
EMD letters
A=Cab equipt. unit or it could mean special order(longer frame, usually for bigger fuel tank)
AC=alternator rectifier on older (2nd gen) units or on newer units AC traction motors
B=Cabless unit (may have a de-commisioned cab)
D=duty as in SD special duty or DD double duty
E=on earlier streamliners-eighteen hundred HP (6axle A-1-A)
E=at the end-EMD rebuild
e=Tier 2 emmisions compliant
F=on earlier streamliners-fourteen hundred HP (4axle)
F=on later units-full body (cowl unit)
GP=general purpose (4axle)
H=head end power equipt
I=isolated “whisper cab”
L=lightweight (may have 3axle A-1-A trucks)
M=north american safty cab or wide cab (without an AC after it implies DC
M=Morrison Knudsen rebuilt unit
MP=multi purpose (4axle switchers)
N=nine hundred HP on earlier switchers
P=passenger unit
R=rebuild
S=six hundred HP on earlier switchers
T=twelve hundred HP on earlier switchers units
T=tunnel motors on SD40s & SD45s
u=rebuilt units in canada
V=VMV re built unit
W=wide cabs in Canada (not sure on this one)
X=experimental unit
-2=modular electrical cabinet
-3=advanced electronics / traction controll
Richard, you were right–A C44-9W is a DC unit, hence different from an AC4400CW (or C44AC, or whatever your favorite railroad decides to call it). David, take note!
I think that GE units might be called “toasters” at times because GE is also known for making appliances. The term is not usually complimentary, but could be taken either way. (On the other hand, I don’t ever remember EMD engines being called “Chevys”, though some SD9s were referred to as “Cadillacs”.)
Didn’t the name “toasters” come from the first -8 wide cabs being called “Techno-toasters”? A shot at the locomotives being another high tech appliance from the GE company.
Man, David, I feel like hitting myself upside the head! What was I thinking when I typed “what is the difference between a C40-8 and a C41-8?” Urrgh, I wasn’t thinking while typing that.
Chad- Have any designations for the GE fleet? Because there are some letters in their fleet that I don’t know. Like the “E” in B39-8E or the “CTE” in AC44 or 45CWCTEs.
Anyways, thanks for all the replies. Keep em’ coming.
…
P.S.)- CShaveRR- Now that I’m thinking about it. I should’ve known that a C44-9W is DC and a AC4400CW is AC. Why would they build to models exactly the same, but call them something different?
the term “techno-toaster” refers to the fact that GE also makes alot of household appliances…such as toasters… and a GE locomotive full of the latest high tech computerized systems and what not got them the nickname of the techno-toaster
csx engineer
CTE stands for “Controlled Tractive Effort.” In helper service, while the high tractive effort of AC units is perfect for unit trains, it can be too much for manifest freights. CTE is mostly a software supplement that allows tractive effort to be attenuated.
first off, the little e in SD70ACe is the designation for teir 3 emmisions standards. I have always heard GE’s called toasters because GE infact makes toasters
Haven’t seen an answer specifically addressing ‘why DC if AC is better’. There are several potential reasons, and there are previous threads on this forum that have discussed them.
NS, for example, didn’t intend to buy AC power because they have a large infrastructure (with experience) in DC traction motor stock and repair. AC motors require a whole additional set of parts, analysis and repair procedures, etc. etc., to say nothing of the additional costs for inverters, testing and analysis equipment, etc. that aren’t common to DC locomotives.
Likewise, even with some of the development costs largely costed down, an AC locomotive has a considerable price premium over the comparable hp in DC – last I looked, that difference would be a good chunk of $1 million for a six-axle unit. If a railroad isn’t intending to make good use of the special characteristics of AC drive (and remember that many of the advantages can’t be used effectively if there is even one DC unit in a given consist) the capital savings may prove more attractive than any economies that can be achieved from ‘better’ train-handling characteristics.
I would have thought that modern inverter AC drives would have lower failure rates and lower overall maintenance cost – but that doesn’t appear to be what happens all too often in the ‘real world’, despite what locomotive manufacturers may have implied or said to railroad purchasing management! I’d be interested to see normalized and accurate statistics that show the relative failure rate and severity of failures in EMDs (with two inverters, one per three-motor truck) vs. GEs (with six, one separate for each traction motor)…
The main difference between the two is AC vs DC, but there are other differences on the carbody itself that distingui***he two.
Same reason some railroads call their “DASH 9-44CW” “C44-9W”. (Or D9-40CW on Norfolk Southern!) Basically, it’s just the preference of the railroad, though it has been a result of the lack of computer standardization between railroads in the past, i.e. “DASH 9-44CW” wouldn’t fit in some railroads’ computers…
Others have answered this one accurately, so I’ll add some more nicknames to it. For example, early GEs were called “U-boats”, a result of their designation being U##B (or U##C, but they were usually still called “boats”). Later, BNSF’s first Dash 9s in GN-inspired colors were called “Goat Boats”! And CIT Financial’s (CEFX) lease fleet of AC4400CWs have been called “Blue Boats” as a result of their color.