# SW1500 cow and calf



## Mister Bill (Jan 30, 2014)

I think they are neat.

Have you ever seen one, picture or real?

Could you post a pic for me?

I am into Santa Fe if given a choice.

Is the calf used in switching or for hauling?

Bill


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## MtRR75 (Nov 27, 2013)

Huh???

You live in TEXAS! There are cattle EVERYWHERE. You haven't see them??

OK... This must be a railroad term that I am not familiar with. Please enlighten those of us who thought you were talking about beef.


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## Big Ed (Jun 16, 2009)

The calf is just like the cow except it is missing the cab and a few more parts.
It was supposed to be a cheaper way to add power to the train, but if the cow broke down it was useless as it had no provisions for the engineer to operate it.


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## Big Ed (Jun 16, 2009)

Now I did capture a cow and a slug. 









There are more pictures (I think) somewhere in here,
http://www.modeltrainforum.com/showthread.php?t=5388

This looks like calf a little, but only has traction motors and gets all it's power from the cow, it is called a slug.

Also with a cow and calf, the calf is semi-permanently coupled to it's switcher via a drawbar.


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## Davidfd85 (Jul 4, 2011)

Hey Ed, that is what I was told is a cow and calf unit on a Santa Fe line. I saw them in the yard area in Temple, TX and asked one of the workers near by. 
I have not seen them out on mainlines but like I said in the yard area.

Might just be called different things in different parts of the country maybe ?

David


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## Big Ed (Jun 16, 2009)

Davidfd85 said:


> Hey Ed, that is what I was told is a cow and calf unit on a Santa Fe line. I saw them in the yard area in Temple, TX and asked one of the workers near by.
> I have not seen them out on mainlines but like I said in the yard area.
> 
> Might just be called different things in different parts of the country maybe ?
> ...



Cow-calf locomotives can be distinguished from the sometimes very similar looking slug and slug mother sets by the fact that both cows and calves are independently powered, while slugs are engineless, and dependent on power from their "mother" units.

Search for cow and calf locomotives, do an image search you will see that calves have exhaust pipes. They have a motor.
Slugs on the other hand is an accessory to a diesel-electric locomotive. It has trucks with traction motors but, unlike a B unit, is unable to move about under its own power. It depends on the cow for power.


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## Big Ed (Jun 16, 2009)

You can see the difference, I put the 2 together.

















Notice the cow and calf, first picture. Look at the body style if you add a cab to the calf it would be just like the cow.

Now look at the slug, second picture. More of just a rectangle box on the frame.

Sorry I couldn't find any Santa Fe's.


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## CREngineer (Jul 11, 2014)

I worked for Penn Central/Conrail and we had both on our hump jobs. We had six axle leader (powered) and a calf ( powered) and later changed to Slugs. The calves were operational, but when we had to operate them on their own, we had to watch from the side door (no cab). The slugs had to be handled with another unit.


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## Big Ed (Jun 16, 2009)

CREngineer said:


> I worked for Penn Central/Conrail and we had both on our hump jobs. We had six axle leader (powered) and a calf ( powered) and later changed to Slugs. The calves were operational, but when we had to operate them on their own, we had to watch from the side door (no cab). The slugs had to be handled with another unit.




Where was the door on the calf was it like a hatch on top that you opened where the cab would have sat? Or was it a side door?
Couldn't they have made it remote control?

Edit,
Sorry I didn't see the side door part.
Got any pictures?


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## Davidfd85 (Jul 4, 2011)

Ok I didn't notice that it was not powered. The SF units that I saw in Temple were powered and that is what I have always thought was a cow and calf unit.

And then again I could have been mistaken about that too. I just found this picture of a SF unit.


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## Big Ed (Jun 16, 2009)

Cool picture, look at the old caboose.:smilie_daumenpos:

That looks like a slug?


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## Davidfd85 (Jul 4, 2011)

I am not sure what they are called now, lol, but that is what I have always thought that they were cow and calf units. 

But then again what does old retired firefighters know about trains lol. 

David


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## morland (Sep 25, 2012)

Here is a picture of an Athearn HO blue box BN calf.


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## Big Ed (Jun 16, 2009)

Here is a good definition of a slugs purpose.

copy and paste,
A slug is used to increase adhesive weight, allowing full horsepower to be applied at a lower speed, thus allowing a higher maximum tractive effort. They are often used in low-speed operations such as switching operations in yards. At low speeds, a diesel-electric locomotive prime mover is capable of producing more electricity than its traction motors can use effectively. Extra power would simply cause the wheels to slip and possibly overheat the traction motors. A slug increases the number of traction motors available to the locomotive, increasing both the pulling and braking power. 
In addition the load on each traction motor is reduced, which helps prevent overheating from excess current. Slugs typically carry ballast to increase their weight and improve traction. Large blocks of concrete are frequently used for this purpose, substituting for the weight of the now-absent prime mover.

The one I photographed was out in a steel plant in Pa, the switcher pulled a lot of weight. The reason for the slug.


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## CREngineer (Jul 11, 2014)

The door for us to see where we were going was on the side. When changing direction or advancing the throttle, we had to duck inside do what we needed and then duck our head outside to see again. We didn't move to fast because of that. No room to stand upright or window/hatch to look out of.


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## Davidfd85 (Jul 4, 2011)

Here is a list of the ones that belong to BNSF/SF. Just scroll down towards the bottom they are listed as yard slugs. 

http://www.rrpicturearchives.net/locoList.aspx?id=BNSF&Page=29


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## Big Ed (Jun 16, 2009)

Yes David they are all slugs, there must be somewhere on that site with pictures of the cows with calves? I didn't look, they should have a different search feature as they do have a ton of trains on the site.

Now sometimes as I think CR mentioned, the calves were converted to slugs when their engines stopped performing. 
So some with the stacks still on could be calves that were converted to slugs. Instead of junking the locomotive they just transformed it into a traction machine.

CR, did you happen to take any pictures from your years of working with the RR?
(PM me if you don't know how to post pictures. Though you need 10 posts to PM someone)

How about one with you moving the calf with your head poking out of the side door? Or one with anyones head poking out?:thumbsup:

In our "safe" world today, I guess they wouldn't allow such a thing to take place.
Maybe?
With a hard hat with a blinking strobe light on top, steel toe boots, while wearing a reflective suit and while being restrained with a safety harness.
That is with a safety person is walking along side ready to catch you. And another to help him if needed.
Along with one walking in the lead with a radio to communicate with you. And one following in the rear.
And also supervisor there to oversee it all.

In our "safe" world today.


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## rkenney (Aug 10, 2013)

Cow and Calf









Slug









Lead Slug


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## Big Ed (Jun 16, 2009)

Now that is *Utterly* ridiculous.


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## Old_Hobo (Feb 20, 2014)

Guys, I think we've milked this one enough.......


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## norgale (Apr 4, 2011)

Boy! I guess.


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## DonR (Oct 18, 2012)

Interesting that the Cow has enough juice to supply tractive power
to the slug in addition to it's own trucks. Would it be likely that
the Cow has a larger amp generator when used with a slug?

Don


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## lajrmdlr (Apr 25, 2014)

Davidfd85 said:


> Ok I didn't notice that it was not powered. The SF units that I saw in Temple were powered and that is what I have always thought was a cow and calf unit.
> 
> And then again I could have been mistaken about that too. I just found this picture of a SF unit.


Your pic is of a powered loco & an unpowered slug. Slugs are just a weighted chassis & traction motors that get their juice from the powered unit.


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## lajrmdlr (Apr 25, 2014)

Here's a pic of ATSF 2419 cow & calf. Its not a SW1500 as Santa Fe never had them. 2419 & calf are TR4A & TR4B basically SW9s.


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## rkenney (Aug 10, 2013)

Cow and Calf are simply A&B units like this old E8 Amtrack lash up.









As already pointed out a 'slug' is just a weighted traction motor.

The b units are self propelled but have no controls (cab) and the original problem of course for many roads was that most turntables could not accommodate an AB set. As a result many more A units were sold than B units (AA units or even ABA as above don't need to be turned).:smokin:


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## Mister Bill (Jan 30, 2014)

Was this type of duo used for switching or for long hauls?

Bill


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## lajrmdlr (Apr 25, 2014)

Mister Bill said:


> Was this type of duo used for switching or for long hauls?
> 
> Bill


A cow & calf were usually used only for switching. Doubt very much if they were used for long hauls by Class 1 RRs . They may have been used local switch jobs close to their yards. Probably did go on long hauls being transferred between yards. Even saw a CSX set in Barstow yard back in 1998. Have no idea why they were so far from home. ~}


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