Vern, Lee and Brad all told me absolutely not. According to Lee, a train engine weighs over ten tons and very small objects won't cause a train to run off the track. Most derailments are caused by breaks or fissures in the rail or wheel defects. A very few derailments are caused by vandalism or sabotage, usually in the form of seriously damaging the tracks, removing or loosening sections of rail, etc. There are close to 2,000 derailments every year, in spite of the fact that most heavily used tracks are inspected visually several times a week and examined monthly with an ultrasound device to find hidden defects.
Inspection focuses mostly on tracks that carry passengers and hazardous materials.
The majority of derailments occur in railroad yards, typically at speeds of around 5 miles an hour. Yard track isn't as well maintained and cars are frequently jostled during switching, which sometimes leads to derailments. The FRA is continually working on improving track inspection methods and ways to improve train safety. But they're understaffed with only 550 people to make sure the industry is adequately checking 230,000 miles of track. Finally getting the FRA on the phone, I spoke with M.B., who confirmed that they probably thought from my earlier e-mail that I was some kind of moronic terrorist.