U.P. "light" Challenger info needed.

: U.P.'s first order of 4-6-6-4s were (I think) originally numbered in : the 8000 series, but as time went on they seem to have been either : renumbered, or later Challenger orders were give lower numbers. : Problem is, nobody in our club models U.P., and other than admitting : to some confusion as to why U.P. numbered some locos they way they : did, they can't be of any help. : : Does anyone have a web reference that can straighten out the question : of exactly what the original Challenger road numbers were, and when : U.P. changed them, Etc.? So far Google hasn't yielded anything useful, : but maybe I'm asking it the wrong questions... : : ~Pete
From the documentation in my Bowser kit:
"The original Union Pacific Challengers were numbered from 3900 to 3939 when they came from Alco, but were renumbered to 3800 to 3839 in 1944 in order to allow space for use on later engines."
"Some engines that had been originally intended for the Union Pacific were diverted to the Denver and Rio Grande Western. These were numbers 3800 to 3805."
The UPs 8000 series steam locos were 4-10-2's, not 4-6-6-2's. A pretty complete list of UP's steam classes and numbers can be found at:
Len

Thanks, Len. The roster answers some of the questions, and I suppose I'd need to find a detailed history of the U.P. to get *all* the information.
~Pete

Yep. The railroads sometimes renumbered locos to make room for other locos of different cleasses. The Challengers on the UP were no exception. You can date the era that you are modelling quickly by the loco numbers. For UP, the change came about when diesels really started showing up on the road.
-- Bob May
rmay at nethere.com http: slash /nav.to slash bobmay http: slash /bobmay dot astronomy.net
Thanks, Len. The roster answers some of the questions, and I suppose I'd need to find a detailed history of the U.P. to get *all* the information.
~Pete

In searching the net for U.P. info I also discovered something else that I'd never known before: there was apparently a period when U.P. only painted the engine's road number on the tender, with no "UNION PACIFIC" visible anywhere.
I assume that like S.P. the numbered tenders came first and were later replaced by the railroad's name when it occurred to someone in the advertising department that they were missing an obvious chance to put their name on several thousand rolling billboards...
~Pete

Just discovered that the Bowser information is wrong: see
for photos (by locomotive number) of nearly all of the U.P. Challengers, and note that except for a few very early photos all of the locos are numbered in the 3900s. (Indeed; the currently operative Challenger is *still* #3985.)
This means that the first 4-6-6-4s were *originally* numbered in the 3800s and were then bumped up to the 3900s, *not* the other way around!
~Pete

Addendum.
I'm probably wrong here. Just noticed that none of those old "light" Challenger photos were taken after the stated change-over date for the re-numbering in 1944, so they most likely indicate that the "light" Challengers were indeed re-numbered down to the 3800s leaving only the newer ones in the 3900s, although I can't find any photographic evidence of this.
What a way to run a railroad.
~Pete