Bill, where does the paper weight come into it ? a decoder shouldn't fail completely because of a derailment, I think there is another reason for it and it could be coincidental.
some help would be if you can let us know what type of decoder and loco you're referring to
I have had sounds failing

thanks

John

I had two Locomotives with Delta Decoders fry because of a faulty Mobile Station recently.

My questions is, do new decoders have some sort of fuse or overload protection?

Usually it won't be the short circuit that damages the decoder, but the spark that comes with it. Sparks generate high voltage spikes at high frequencies and these travel through the tracks as well as radiating in the air.

The controller should shut down the instant a short circuit is detected, but if the problem occurs far from the power feed the resistance in the tracks and the feeder cables might delay the cut-off, allowing sparking to go on for longer.

I've had many sound decoders (sound) failing and lately sent 5 back to ESU for repair but never had a decoder fail due to a derailment and yes I had decoders fail and than reset them and they worked fine afterwards which to me is a bit of a mystery., and one of these occurrences happened when ESU informed me the decoder I've sent back to them there was nothing wrong with it.
I also had a few Märklin decoders from clients who bought the loco in for conversions and failed do to a faulty motor., my latest repair (which I can't fulfill) is a overhead maintenance car with various functions, e.g. raising pantograph, movable working bridge, raising and lowering of working bridge and the rail car itself doesn't move at all, all I get out of it is the auxiliary sound functions. I'll get in contact with Märklin and see if they can repair the rail car (39970)., my friend said don't worry about it but I think it's worth the repair depending how much if anything Märklin will charge.
I've had my share of derailments but mainly with carriages and not with locos, when cleaning the pukos with a fine diamond plate (own design) and I forget to turn of my ECoS there are coming substantial sparks from it and most the time it shuts itself down.
So far I'm aware ESU decoders are protected from shorts but how far this protection goes I've got no idea nor am I qualified to make any technical or electronic assumptions.

John