how do i find out how much my older trains and sets are worth now?
They are worth what someone is willing to pay.
Look on eBay to get a general idea.
Usually, unless it says Lionel on the box, not that much.
Timothy
This question comes up often. Checking EBay is the best option. There are two markets for old trains, modellers and collectors. Modellers run trains and generally are only interested in old trains if they are considerably cheaper than new equivelents (which generally will be more detailed and run better, of course there are exceptions) or where there are no recent equivelents. Rarely will they pay a lot for an old train. Most people on this board, including myself, are modellers.
Collectors are interested in examples of a particular maker, or period or theme etc. for the sake of having the models, not for running them. Value to collectors depends on the rarity of the item (which could be an unusual variation on an otherwise common item), condition (if in original boxes will increase value) and, perhaps most importantly, whether the particular item is fashionable to collect. Unless you know the market well (I don't) collectors value is hard to judge. Most old trains have little collectors value -but a few do.
Hamish
The value depends a little on why you need to know the value. If you're planning on selling them to fund your retirement, they won't be worth much. If you're planning on a rider on an insurance policy, you may be able to use the cost of new equipment as the replacement value.
This is the site you need to go to, classic toy trains:
http://cs.trains.com/trccs/forums/95.aspx