I dont know much but what I do know is depending on how old and what company made them there is a possibility for a substantial proffit! I would take the time and do the proper research yourself before getting rid of them
Possibly, but it would be a few select pieces that have special collector value.
More than likely, they're just used model trains, with similar resale value to used RC cars (which is to say, for the most part, crap). Pretty much the only model train stuff that's been around long enough to have serious collector value outside of stuff that was made to be collectible (and started out expensive) is gonna be pre-war O and G scale, and a handful of early HO bits. N scale, Z scale and T-gauge are all too new; N scale emerged commercially in the sixties.
There are, of course, some very high end makers of N-scale. Just investigate thoroughly before selling, especially locomotives.