My fathers 1950's S gauge American Flyer - Model Railroader Magazine

You'll probably have better luck posting this in the Classic Toy Trains forum, I think. A can give you a bit of insight, as I offset the cost of my modern HO-gauge hobby by dealing in vintage trains.

Parts are generally available from specialty vendors and I've not found it all that difficult just to get sets running for hobby/play purposes. One common trick for non-running locos is simply to separate the body from the motor unit, soak it (the motor) overnight in paint thinner, let it dry, relube and try it out. About 90% of the non-runners I've dealt with came right back to life this way - they were basically just clogged up with years of grime, dirt and dust.

Now, realize that 'restoring' a train is different than just a "clean up" and "get running." Many things you would do to 'clean up and run' an old train set will actually detract from it's value as a collectible - in the not-that-likely event it even has much value. You will never 'restore' a train and have the same value as a mint original, but restoring to even have _some_ value remain is a painstaking and precise process. e.g. you'll need to buy old locos to get original parts rather than getting reproduction parts from the vendors I mention above...

On that note: a word of caution. These things are rarely worth anything close to what people think they are. Yes, original equipment in great condition with original boxes can be modestly valuable, and can be quite valuable if it's a rare model/version - and mostly if it's pre-war vintage.  But the vast majority of "found it in the attic" stuff is neither rare nor in good enough condition to have much value. There's simply too much of it out there and still available.

One quick way to judge era: If it's made out of plastic, it's vastly unlikely to have significant value.

My father-in-law had a huge set of Lionel trains from the early 1950's. They were in great condition, packed up carefully in the original boxes since the late 1950's. He had 4 different loco/car trains, tons of accessories, track, switches, transformer, the works. ALL in original packaging! He was convinced it was worth many thousands. As a "dealer" I'd have offered him $500 for it and expected to sell it for $750-1000 at most - and that only if I broke it up, sold the few items with any real value individually and gave the rest away to someone who wanted a nice round-the-Christmas-tree set. (Ironically, one fringe benefit of dealing in this stuff is playing choo-choo Santa. I often buy big collections of stuff just for a few items of value. The rest of it is cool, fun, nostalgic and largely worthless, so it goes off to live  around the christmas trees of every family I know with kids...)

So if you want to get them there, get them running and set them up for fun, nostalgia or (best of all) to share the joy of toy trains with a child, more power to you! It may be easier than you think. There are some good books out there on how to get them going, and likely lots of very detailed specific advice available over on the CTT forum. Have fun, enjoy and you'll have a great set. As an added bonus, most people will think they're worth a lot of money!

However, if you're thinking of reaping a tidy little sum by selling them, the odds are against you. I'm not saying it's impossible, but definitely do some research, see what similar things are selling for in the relevant stores, and on E-Bay, and be particularly careful before doing any 'work' on them that you aren't causing degradation of value.