Probably the derailment mechanism from a shunt is a signal suddenly dropping to red without prior signals reflecting it (Approach, etc). That could cause the engineer to have to put the train in emergency, and that sudden, sharp braking has caused derailments on some occasions. Usually not, but it is certainly possible.last summer a couple ecoterrorists were caught putting shunts between tracks on BNSF tracks north of Everett. I am not sure what this is supposed to do, but they said it could cause derailment.
King 5 news report
They threw the book at the perps, though. They are facing 20 years. One pled out and will likely have a much shorter sentence, but the other took it to trial and was found guilty. I imagine she's going spend a long, long time as a guest of the Federal prison system.