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  • Member since
    March, 2018
  • 4 posts
Posted by Eugen on Tuesday, March 20, 2018 2:29 PM


my name is Eugen. I’m from Belarus.  I am going to construct a high detailed model of early Challenger and I assume that the type of its frame is bar frame. This is an important moment and let me explain why.

 According to the types of locomotive frames (https://en.wikipedia.org/wiki/Locomotive_frame) the bar frame is constructed from steel bars that have the thickness about 4-7 inches. And it principally differs from the locomotive bed that is single-piece casting. 

 I chose early 4-6-6-4 Challenger to build my model because I hoped that it has bar frame type. For now I cannot make sure of it. Could you clear this problem? Maybe you can send me a part of drawing to see the type of frame it has. 

 I suspect that early models of Challenger have bar frame with sheets that are made by casting. But in the same time it is bar frame (not cast steel bed). Maybe from this point a mess in the terminology begins. Possibly some models of Challenger have locomotive bed (later models?). 

 I principally need bar frame. Here is an example – a drawing of the bar frame element: http://www.nwhs.org/archivesdb/thumbs/dwg/NW-F26819.07-02-1946.gif

the same type I need. 


But not actually locomotive bed like this: https://tinyurl.com/y8jsg9zl

(it is a drawing of one of the Challenger bed).

Unfortunately nobody has given me an exact answer what type of frame the early 4-6-6-4 Challenger has. Some peoples said that the first models have bar frame, other said that all models of Challeger have locomotive bed (i.e. they all have cast steel bed). The discussion on this item becomes confused because of the specific of the terminology as well as deviation in Russian and English terms.


Thanking in advance.

Best wishes,


  • Member since
    August, 2010
  • From: Henrico, VA
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Posted by Firelock76 on Wednesday, March 21, 2018 7:13 PM

Welcome aboard Eugen!

To my knowledge the Challengers as produced by ALCO had cast steel frames, not frames built up from plates or bars, cast frames were pretty much the standard here in the US by the time the Challengers came along. 

If you're looking for Challenger drawings possible these organizations can help you.

https://library.syr.edu/    This is the Syracuse University Library website.  All of ALCO's drawings and records are in the library's collection.  Select "Classic Catalog" or "Special Collections" on the website and go from there.

http://modelsteamengines.tripod.com/misc_drawings.html   This site may prove useful, according to what I see there they can reproduce locomotive production drawings, what the cost might be I don't know, you'd have to ask.

www.ahts.org  This is the ALCO Historical Society's website

www.rlhs.org    This is the Railroad and Locomotive Historical Society's website.

Good luck!  And again, welcome aboard!

  • Member since
    January, 2015
  • 1,383 posts
Posted by kgbw49 on Wednesday, March 21, 2018 8:09 PM

Hello, Eugen and welcome!

I am thinking that the CSA-1 and CSA-2 Challengers (3900-3939 in first numbering) were cast steel because they were the first new freight engines ordered after the Great DepresDino. and were fully roller-bearing equipped 

They had the same 69 inch drivers as the later Challenger orders and in fact, after World War II actually received new heavier front end engines identical to those of the later Challengers.

Here is a picture of one such rebuilt early Challenger doubleheading with a Big Boy:

https://www.google.com/imgres?imgurl=http%3A%2F%2Fwww.steam locomotive.com%2Fwhyte%2F4-6-6-4%2FUSA%2Fphotos%2Fup3828-hechtkoff.jpg&imgrefurl=https%3A%2F%2Fforums.dovetailgames.com%2Fthreads%2Funion-pacific-cheyenne-to-rock-springs.2933%2F&docid=dcRmSN1EsLt_cM&tbnid=LjSVUDnun_gccM%3A&vet=1&w=1024&h=595&hl=en-us&client=safari&bih=917&biw=1366&ved=2ahUKEwjCxPXD3P7ZAhXr44MKHTfxDO0QxiAoDnoECAAQJg&iact=c&ictx=1


  • Member since
    January, 2015
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Posted by kgbw49 on Wednesday, March 28, 2018 10:11 PM

Interesting web site with some Challenger info.



  • Member since
    January, 2015
  • 1,383 posts
Posted by kgbw49 on Wednesday, March 28, 2018 10:19 PM

This web page has data indicating the Challenger CSA-1 and CSA-2 classes had integral cast steel engine bed frames.

So they did not have built-up frames.




  • Member since
    February, 2005
  • 1,799 posts
Posted by timz on Saturday, March 31, 2018 4:26 PM

...were cast steel... and were fully roller-bearing equipped

When new, the first forty 4-6+6-4s had bar frames. Roller bearings on tender, trailer and engine trucks-- not on the drivers.

  • Member since
    January, 2015
  • 1,383 posts
Posted by kgbw49 on Saturday, March 31, 2018 5:39 PM

Interesting. The write up on steamlocomotive.com indicates otherwise.

I have William Kratville’s books stored away. When I have time I’ll have to dig them out and see what he says.

  • Member since
    September, 2003
  • 6,803 posts
Posted by Overmod on Saturday, March 31, 2018 6:04 PM

Kratville's book on Challengers has definitive information, but my copy is in storage.  The only thing on steamlocomotive.com indicating cast beds on the Fetter Challengers is a quote from Bruce's book (which I think is worded by them to give a mistaken impression that all Challengers had the refinements of the later ones) - my copy of Bruce is likewise in storage so someone else should check the exact wording he used. 

Here might be the place to remind the unwary that cast-steel frames are NOT bar frames ... but not cast-steel engine beds, either.  Each side of a cast-steel frame is a single flat casting, but the crossmembers are still fabricated and the cylinder saddle likely made separate.  Only the bed puts the whole frame and cylinders inherently and permanently 'in tram'.

  • Member since
    January, 2015
  • 1,383 posts
Posted by kgbw49 on Sunday, April 01, 2018 9:13 PM

Overmod, you are spot on as usual!

I dug out my copy of William Kratville’s “The Challenger Locomotives”.

On pages 9-13 there is a reprint from Railway Age magazine describing the construction of the Fetters Challengers, along with pictures of the frame.

The frames are described as being “of the cast-steel bar type”, with various sections bolted together, including bolting on of the cylinders.

Kratville indicates that for the later Jabelmann Challengers, they were equipped with one-piece cast engine beds with the cylinders integral to that large casting.

Kratville also notes that after World War II, ten of the Fetters Challengers had their front engines swapped out and replaced with new one-piece cast engine beds with integral cylinders, with the rear engines remaining as bar-type frames.

The book contains several pictures of the Fetters Challengers - both unmodified units and modified units - operating in 1957. While still short in terms of what their useful life might have been, at least some of the units had 21 years in operation.

Actually, it was very entertaining to pull the book out and go through it again!


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