Here is the link for Lionel Parts on the Polar Express gateman.
https://www.lionelsupport.com/...man-Plug-Expand-Play
The modern solenoid with plastic former tube the plunger has to slide freely in
Then in the plug and pray versions, there is this modern PCB and yes, there are diodes and capacitors, also appears to be PTCs, but unsure of exactly how this is wired at the moment and the true function. Point being, if it really worked and protected the coil- we would not have topics about damage and people replacing a gateman 4 times in a row.