It is the EC-5.
https://www.uprr.com/newsinfo/releases/capital_investment/2005/1216_ec5.shtml
Saw this being pulled on UP's section of track on the Rochelle IL webcam a few moments ago. It's different than the EC-4's I found when I googled UP Inspection car. Never saw one before so I thought I would share.
Henry
COB Potomac & Northern
Shenandoah Valley