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ATSF Locomotive numbering

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  • Member since
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  • From: Phoenix, AZ
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ATSF Locomotive numbering
Posted by bearman on Sunday, March 19, 2017 9:04 AM

I'm in the market for an ATSF GP 7 and found several Athearn Genesis on-line.  What I also found was that two of the locos were numbered 2789 & 2789A, and another two were numbered 2790 & 2790A.  Does anyone know the significance of the way these locomotives are numbered?

Bear "It's all about having fun."

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Posted by mbinsewi on Sunday, March 19, 2017 9:24 AM

I seen those too.  I had to go back for a second look when I read your post.  It looks like the "A" is a GP7B, and maybe they are numbered like that to represent  matched A and B sets.  The 2789 and the 2789A (which is a B unit, no cab) are a matched set.  Maybe?

I don't know anything about how the ATSF numbered their locos, just a "maybe"?

Mike.

EDIT:  Farther down the page, that Atlas, Kato, made in Japan would be a good buy, considering the bids start out at $30.

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Posted by richhotrain on Sunday, March 19, 2017 9:41 AM

Here is a link to the entire ATSF diesel roster.

http://old.atsfrr.org/resources/CrossetGene/ATSF_all-time%20diesel%20roster/index.htm

Click on the 2750-2999 Roster.

Rich

Alton Junction

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Posted by zstripe on Sunday, March 19, 2017 9:42 AM

The numbers with the A are ''road slugs''..no prime movers...they must be controlled by the Mother engine. The cab was there, but had no control also. A lot of Railroads had different names for them. Like hump yard slugs etc. Some even reffered to them as ''B'' units.

Take Care! Big Smile

Frank

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Posted by bearman on Sunday, March 19, 2017 9:45 AM

Aha, I think it is clear to me now.  I do not want the A unit.

Bear "It's all about having fun."

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Posted by Heartland Division CB&Q on Sunday, March 19, 2017 9:49 AM

Google shows images of 2790A.

It is a complete locomotive except it has no cab. ..... Originally, 2790 was the controlling locomotive, and 2790A was the booster locomotive. 

GARRY

HEARTLAND DIVISION, CB&Q RR

EVERYWHERE LOST; WE HUSTLE OUR CABOOSE FOR YOU

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Posted by peahrens on Sunday, March 19, 2017 9:54 AM

zstripe
The numbers with the A are ''road slugs''..no prime movers...they must be controlled by the Mother engine. The cab was there, but had no control also. A lot of Railroads had different names for them. Like hump yard slugs etc. Some even reffered to them as ''B'' units.

For anyone else like me who is not aware of the "slug" setup.  I was aware of cab-less B unit Geeps but did not recall the difference between a B and a slug.  More info here:

https://en.wikipedia.org/wiki/Slug_(railroad)

 

Paul

Modeling HO with a transition era UP bent

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Posted by oldline1 on Sunday, March 19, 2017 9:57 AM

These units were GP-7's ordered as "B" units. They were fully functional GP-7's but without cabs. They were originally made to mate with regular cab equipped GP-7's but later on were used with other units. I believe the Santa Fe also had GP-9B units.

There were operator controls inside the area where the cab should be, hence the porthole for the hostler to use when he needed to operate the unit by itself for servicing or maintenance.

They were not "slugs". At the time they were built there were no slugs. 

A slug has no engine, generator or mechanical ability to generate power as these"B" units. They are only weighted bodies with traction motor equipped trucks used to assist and powered by a mother locomotive.

A "B" unit is capable of generating power itself and is technically a locomotive.

Roger Huber

Deer Creek Locomotive Works

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Posted by 7j43k on Sunday, March 19, 2017 10:57 AM

Here is the Athearn announcement for these locomotives:

 

 

You can plainly see the "A"'s described as B units.

I don't follow Santa Fe much; but I do know that UP, after they'd had them for awhile, mixed their GP9B's up with other assorted diesels.

 

Ed

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Posted by richhotrain on Sunday, March 19, 2017 11:25 AM

You would probably be better off just buying two lead units, like the 2789 and 2790.  That would definitely be prototypical.

Rich

Alton Junction

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Posted by bearman on Sunday, March 19, 2017 2:32 PM

And that is what I have done, Rich.  Ordered 2790.

Bear "It's all about having fun."

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Posted by ACY Tom on Sunday, March 19, 2017 3:24 PM

Mbinsewi got it right, immediately.

Worey's book Iron Horses of the Santa Fe Trail (SW RR Hist. Soc., 1965) says these were all 1500 h.p. GP7's built in April, 1953. None of them was a slug. They all had prime movers, but the ones with "A" suffixes were cabless boosters. They all had dynamic brakes. They were delivered in Santa Fe's classic black and silver scheme. 

They were part of Santa Fe class 2650, which ranged from 2650 to 2893, and 2788A to 2792A (244 cab units and 5 cabless boosters).

The cab units weighed 249,000 pounds and had a tractive effort of 62,250 pounds. The boosters weighed 247,150 pounds and had a tractive effort of 61,790 pounds.

With the delivery of this massive order during 1950-1953, Santa Fe took a giant step towards total dieselization, and the last steam runs were made in New Mexico in August, 1957.

Tom 

 

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