P42s behind GEVOs

In today's Virtual Railfan grab bag, Amtrak P42 #205 was spotted trailing behind a few UP GEVOs in Kearny, NE; far from Amtrak trackage. This isn't the first time a Genesis has been spotted behind the lead engines of a freight train, and I assume this is likely for transporting these engines for routine maintenance. If this is the case, then does anyone happen to know where these P42s are maintained and who usually does this work outside of Beech Groove?

If 205 is going somewhere else for work. All the better to get more locos back to full operation sooner.

https://youtu.be/WnsKQbeRVI8?t=942
My "reliable sources" tell me that California Zephyr #5-29 set off the engine in bad order at Leyden, Colorado. Mechanical crews were then able to at least get it in a movable state that would prevent further damage and UP is now sending it back east to Amtrak. Depending on the amount of additional work needed, Amtrak will either fix it in Chicago or send it to Beech Grove or Albany.