This may seem weird, but when I was a kid we used to put coins on the railroad tracks, watch the train go by, the pick up our flattened coins (which were rather warm by then). I remember being warned to stop it because leaving coins on the track could cause the train to derail. We kinda doubted it but found other mischief to get into.
Can putting stuff (coins or whatever) really cause train derailment??
Not sure about the coins, but I know a fellow whose friends would slather the rails along a significant grade with hog grease at butchering season to make the steam loco’s belch extra soot; maybe even stall the train until a helper engine could arrive.
Sufficiently large stuff, yes. Coins, no.
Never heard that it could and we put pennies on tracks all the time.