I have bought numerous trains from sellers in the UK and some other miscellaneous items from other places in the EU. Never more than a few hundred dollars, and have never paid any kind of import fee. IMO, proper marking on the customs form is important - clearly identify the items as toys.
A train friend in the UK told me a horror story... after learning that they were both train guys, a US guest at his B&B sent him a box of miscellaneous model train stuff as a gift - minimal value. The customs form was marked "train parts", which led the UK customs people to treat them as industrial supplies rather than model/toy trains. As a result, he had to pay a duty of over $100 to pick up this "gift".
I have another friend in Canada who bought several items from Menards. He didn't have to pay a duty, but UPS hit him with a hefty charge for handling an international shipment - it was about $80 IIRC.
Also, overseas prices usually include VAT of around 20%, which a foreign buyer doesn't need to pay. Some sellers automatically discount for this, some do it if asked, and sometimes the only way to get it back is to submit a form (which probably isn't worth the hassle).
Good luck, and please report back with the result.
