That's the one but I'm only using the chassis.
I have a complete Challenger boiler and cab that I picked up about two years ago, that has all the domes and most everything else on it.
The seller included most of the steam tubes, valve and side rods and brackets with the chassis.
At a quick inspection, I seem to be missing this one steam supply tube, a few of the trunion link brackets, 2-reverse link, 1-crosshead & guide and the rear trailing truck.
The boiler and cab are all packed away in preparation of us moving soon so I'm sure I'll find other things that are missing once I start putting this back together.
Is the tender that was used on the Challenger the same as they used on the Bigboy ?
If so, then I have a brass tender for it.
Looking thru old photos of some of the Challenger engines, they seemed to have used a variety of tenders with these locomotives.