Abandoned former AMTRAK passenger cars

[Electroliner 1935]

This popped up on YouTube and wonder if anyone knows anything about these cars?

https://www.youtube.com/watch?v=Kfg8zUQCbiM

[CMStPnP]

I think that is one of the late Texas Eagles from the 1980's, judging from the random skeletons on board it has been waiting in the siding for a while on one of the rarely late and "scheduled"  UP freight trains to pass.