Very helpful, Thank you!

Hello! My husband is wanting to get started with model trains and I am thinking about getting him something train related for Christmas. He really just wants something to put around the Christmas tree each year and he would like for it be something he and our son can add on to each year. Because it will only be out for about one month out of the year I guess it doesn't have to be anything super fancy. I was thinking about getting him the front part of the train (please excuse my train terminology ignorance) this Christmas, but I have no idea what I'm looking at here. Any advice would be greatly appreciated. Thanks!