I know this happened a lot in Montana back in the 60's and 70's on the Milwaukee Railroad. They were notorious for derailments due to bad rails and ties. I remember seeing pictures that my neighbor took of some of these incidents, as he worked on the recovery side. Lots of car carriers on their sides, and it was the same thing...dig a trench and push them in. From my understanding, the car companies didn't want the liability if something happened with these cars if they were recovered and sold. All the tracks were pulled up back in the 80's for scrap and the right of ways reverted back to the counties they passed thru. Not sure a metal detector would do much good, as there are also 100 years worth of spikes and plates laying out there too. lol
