Okay, I’ve been a model railroader and a railfan for a good number of decades now, but I ran across a new one for me.
I took a “road trip” west and on the way back home on October 15 I stopped by Ft. Smith, Arkansas to see if I could get a photo or two of an Arkansas & Missouri Alco. I found one in operation, but in their yard near the freight car repair shop was an odd Union Pacific “flat car with hood”. There was a dog who appeared pretty settled under the one end of the car (visible in one of the photos) which suggested to me that it might be better NOT to go up close to the car to look for a control panel or something that might explain the purpose. Note that there are not any M.U. cables coming off of this thing. My GUESS is that it might be a generator unit for producing emergency light or other power at remote locations.
So, Union Pacific fans: (a) can you tell me what this is and (b) has anyone out there made a model of it?


Bill
Found on a roster of UP passenger equipment:
UPP 403, flat car fitted with training aids. Doubtful that it has an operable engine - no fuel tanks.
Chuck (Modeling Central Japan in September, 1964)
Googling “UPP 403” gave me THIS, and further investigation THIS.
Wayne
Its a portable load tester. There is an electrical control box on the one end and 3 dynamic brake grids on the other. They hook up the main generator of a locomotive to the control box, then rev up the locomotive and use the dynamic brake grids to put a load on the main generator. When they finish testing the engine they would hook the power cables back up to the power system on the locomotive and ready it for use.
This would most be used in shop locations that had an overhead crane that could do main generator changes, but did not have a stationary load tester themselves. It is not used in a train or while the engine is moving. 99.99999% of the time it will be just sitting someplace. If you build a model of it you might run it in a train once in the history of your layout.
For something that doesn’t move much it looks prettty well kept up.
Thanks, everyone. Now I can label the photo file.
So many railroads have “cleaned up” their shop and storage areas, eliminating many relics that used to be of interest to me and my camera. It was a joy to get out and find something different and interesting.
And it’s still a challenge sitting out there to the really serious UP modeler!
Bill