I recently purchased this photo from the folks helping to liquidate Ward Kimball's estate. It appears to be a photo taken by Ward during his visit with Walt and Ollie to Dick Jackson's backyard railroad, which featured quite prominently in Michael Broggie's book as directly igniting Walt's interesting in building Carolwood. The photo shows Jackson's Colorado Central No. 900 fully steamed up next to another engine, Southern Pacific No. 631? Much was written about in Broggie's book about the 900 but I have no info on the other engine. Does anyone here know much about its origin?

Here is the pic from The Walt Disney Railroad showing Ward holding what looks like the very camera used to take the picture above.