For most of the 20th century, the go-to Christmas gifts for boys were model trains. This weekend you can relive cherished childhood memories at the Greenberg Train and Toy Show on Saturday and Sunday, Dec. 20 and 21, at the Richmond Raceway Complex. There will be hundreds of model trains, accessories and collectibles for sale as well as huge train layouts, children’s activities and modeling seminars. It’s a formula that’s made the Greenberg toy showcases one of the most respected model railroading events in the United States since the mid-’70s. The show hours are 10 a.m.-4 p.m. Admission is $8, good for both days and children younger than 12 are free. And if you need more model trains in your life, check out the River City 3 Railers Holiday Display at the Great Big Greenhouse in Huguenot Village Shopping Center on view every Friday, Saturday and Sunday through Jan. 10. richmondracewaycomplex.com.