View Full Version : What is a slug?
06-23-2001, 02:44 AM
I guess you would call it a slug car but what is it?
A Slug is a switch engine that does not have a cab. It is coupled to a switch engine with a cab for added power. They are used in hump yards where the switchers have to push 100+ car trains over the hump.
Locomotives have power in excess of what it can use at low speeds. So "slugs" are employed to take advantage of this "extra" power.
A slug is an ENGINE-LESS and (and most of the time CAB-LESS) "powered unit" that uses electricity generated by a second Locomotive to power its traction motors.
An example of a premium slug would be the 80 built by precision national back in 1988 for CSX. They were road slugs rebuilt from GP30's & 35's. They had control cabs, dynamic brakes & were also fuel tenders for thier "mother" units.
06-23-2001, 10:59 AM
so are you saying that if they know the train has too much power then they need they will add the so called slug?
06-24-2001, 04:42 PM
Think of it this way: A locomotive such as the GP-38 has one powerplant, with four traction motors on the axles which allow it to go 60mph. But say, this loco is used in a local yard, and can only go 20 mph anyway, so the powerplant (Which consists of a diesel engine hooked to a huge generator) has lots of extra amps to spare. So, you take a second loco, an obsolete one usually, take out the powerplant, add a huge chunk of concrete for weight, and run cables to it from the mother, and the powerplant now supplies power to 8 traction motors, and has is using all of its' amps at 20 mph. Since powerplants are expensive, this saves money. The Kansas City Southern, which had horrible track used these on main line runs, since the track was so bad, you couldn't exceed 20 mph anyway. It really isn't that common, and all the examples are home-built units.
A second combo, with two powered units, one with a cab and the other without, is called a Cow and Calf.
06-29-2001, 09:49 AM
By the way, the physical deisel is referred to as the "prime mover".
Heres a pic:
06-30-2001, 04:58 PM
It's called a prime mover because if the diesel goes dead, the whole locomotive is dead. Since there are multiple traction engines, if one of those shorts out, it can be isolated, allowing the unit to continue, though at a reduced amount of traction power.
08-01-2001, 12:52 PM
Here's a couple more slugs:
BN ET-2 at Minneapolis, MN on 5/23/84
BN #6291 at Galesburg, IL on 9/17/93
08-01-2001, 01:13 PM
What you are reffering to as slugs are boosters. A slug can be any locomotive, self powered or not that is not equipped with a cab that meets FRA in service occupiable standards. Even a locomotive with a cracked windshield can be MU'd in "Trail only" as a slug.
08-01-2001, 01:32 PM
Wasnt the sencond BN a rebuilt SD9 that served as a test and was actually still an engine? I think they only did two and mabye MK was the rebuilder
08-01-2001, 09:51 PM
Ok this one looks "taller" then the other one I seen....
>Here's a couple more slugs:
>BN ET-2 at Minneapolis, MN on
>BN #6291 at Galesburg, IL on
08-02-2001, 01:35 PM
I don't believe that BN #6291 is self powered, given the lack of exhaust stacks and radiators. The louvers on the sides are (I believe) intakes for the traction motor blowers. Number 6291 is listed on the BN roster as a class TEBUC6, zero horsepower. It was dervived from former BN SD-9 #6146, which was former CB&Q SD-9 #344. I'm researching more info on it. Meanwhile, here's another slug, sandwiched between two GP-40's. I've included a roof shot, evidence that there is no prime mover aboard.
MNA #4164 at Cotter, AR on 4/30/94
08-02-2001, 05:09 PM
Join the Army! Meet Interesting people! Kill them!
Yeah good point. someone just made a skin for the GP35 slug CSX in the stealth scheme.
08-02-2001, 06:54 PM
OK milwaukeefan, this is for you. Is it a slug or a booster?
MILW SE3 at Bensenville, IL in April 1981
MILW F-7 83A at Bensenville, IL in April 1981
08-02-2001, 07:56 PM
Join the Army! Meet Interesting people! Kill them!
Slug. I think they converted a few F7bs in 1979 to slugs which stayed in F consists for transfer runs out of Bensenville and also for transfer runs in St. Paul. They did not last to the end though
08-04-2001, 04:45 PM
Things aren't always what they seem...A lot of Fx B-Units were converted to contain HEP units and even large water tanks and boilers for train-line steam. Some Amtrak F40ph's have been converted into Baggage cars and control cabs without any power whatsoever. EMD has test units without traction motors just to test the prime-movers, sometimes parked at high elevations...Who knows what else? I think there was once even a loco which was used as a caboose, but I don't remember for sure...
08-04-2001, 06:27 PM
LAST EDITED ON Aug-04-01 AT 06:47PM (EST)[p]I understand. I was just trying to stay within the scope of the original question: "What Is A Slug?". They can also be used as fuel tenders, but does that qualify it as a slug?.
Amtrak #400 fuel tender at 18th St., Chicago in June, 1978 Contains Diesel #2 9300 Gal.
08-04-2001, 08:07 PM
shouldnt because the traction motors are not working. And I realize the other uses for the F and E hulks but they arent considered slugs either. LIRR had for many years Cab Control cars which were just FAs And F's with control stands and cabs that you could control the train from. In the case of the Milwaukee slug if they still were in passenger service in 81' as they would be for that F7B to be a HEP generator they would not have survived to the Soo Line merger date and would have been the next Rock Island.
08-04-2001, 08:43 PM
LAST EDITED ON Aug-04-01 AT 08:47PM (EST)[p]Yes, but MY definition of a Slug woud be that it has traction motors, but no prime mover. If there is an Official definition, I would like to hear of it.
On the other subject, my understanding was that the LI FA's provided HEP, and that the original Alco 251's were retained for that purpose. Correct me if I'm wrong.
LI FA-? 616 June, 1980
Sorry, don't know where I was. I was at a sales meeting, they gave me a rental car, I took pictures of trains. What the heck's the matter with me?
08-04-2001, 11:00 PM
Is this a slug?
CNW BU-3 at Proviso, IL on 2/14/65
08-05-2001, 02:15 AM
FWIW, My understanding from all the years I've been a "foamer" and the usage that I've grown up with here in the NEC is basically..... If it has traction motors but no Prime Mover then it is a slug! If it has traction motors, a Prime Mover and no cab then it is a Calf..... Control Cabs have neither traction motors nor Prime Movers.... They may have HEP units (even if it is the old prime mover converted to HEP usage ala the Long Island) or baggage compartments like the Amtrak Cabbage... Please enlighten me if I am wrong....
08-05-2001, 06:53 PM
SP had slugs too.
SP #1609, Tucson, AZ on 11/21/85
SP #1013, Tucson, AZ on 11/21/85
05-23-2002, 11:33 PM
Boy-O-Boy, that was really quite a "Slug-Out" !! Sorry guys; I just couldn't resist that !!!!
Ron K of Rockford
06-18-2002, 07:46 PM
LAST EDITED ON Jun-18-02 AT 07:53PM (EDT)[p]LAST EDITED ON Jun-18-02 AT 07:51*PM (EDT)
WHERE IN MINNEAPOLIS?!?!
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