My husband has a few brand new still in plastic wrap, Model Railroader magazines.  Can I post them on this site or does anyone know where I can swap them.

Magazines are not allowed.  Sorry, I have no idea where you can trade them.

Jody is right.  Magazines are not considered books because they do not have ISBN numbers and they also contain advertising.

We can not risk sending them by media mail.  You would need to send them first class or parcel post.  PBS has set up policies to be very careful about media mail standards.  

Connie, magazines can be traded on Bookmooch...just put the term in your search engine & you'll find the site. 

Here's the Help Center page that tells you what can and cannot be posted:

What can be posted for swapping here?

Title Trader also allows the posting of magazines

You could offer them in the RAOK forum here or as freebies with an order from your shelf, in the Book Bazaar...