Another important step in cases like this is to have a good relationship with the scrap dealers. If you can alert them quickly enough, they can help catch the perps. Let them know to be suspicious of railroad related goods, and educate them on what might be taken. (High gauge copper wire is high gauge copper wire, but tie & fish plates, rail, spikes, grabirons, and other items are pretty definitively railroad related.)

The problem is the ones who operate on the fringe of the law. Reputable scrap dealers will require proof of ownership of railroad materials, at least here in Washington state. I know that since I often have to provide the proof, especially if we take a pickup load of random scrap from a small project.

The problem is that there always seems to be one scrap dealer that looks the other way, and doesn't pay very close attention to what's in that ratty old dump truck of scrap they're buying.

Railroad special agents work pretty hard on this stuff, and they watch things pretty closely. At least around here they tend to keep an eye on the scrap yards.

They're not all NCSI candidates though. Many years ago I had a special agent visit a railroad I was working for. He was from the UP and was investigating some stolen rail. For whatever reason, he was of the opinion we might have acquired some of it. "Can I take a look around the property? We're missing some rail!" "Sure, no problem... Say, what size rail are you missing?" "It's a bunch of new 133RE..." I laughed and replied "Well, you can have any stick of 133 you find, no argument from me! By the way, around here, we think 'big steel' is 90#.... Happy Hunting!"