... ok, correct me if I'm wrong, but are these some type of drag detectors? ... spotted just south of the Sellars Rd NS crossing in Moraine, OH, just south of the Truck and Bus group...
That's precisely what it is. Here's another type, at Tunnel 3 on the Moffat: http://www.trainboard.com/railimages/data/629/T3_EP.jpg