You may stay above water with excess layout building supplies (i.e., unused track, scenery items, wiring components, etc...) that you over-purchased. But the trains themselves? No way are you NOT gonna take a hit -- unless you have something that happens to be that year's "hot item". The list is VERY short indeed... and in years past it's included the Lionel black VL Hudson, Lionel Milwaukee Road S-3 (especially #261), Lionel VL Ethanol tanker with freight-sounds, along with -- of course -- the Lionel die-cast GEVO hybrid and other die-cast ES44 locomotives.
Fair enough. I model On30, not 3-rail, so I'm totally unfamiliar with the values of any of that stuff. All I've been getting rid of were excess supplies and some structures that were good to start with.