I've been a train nut forever.
Started out with American Flyer when I was little - Dad bought two sets, one for me and one for my brother. We combined them onto one layout which, of course, would only come out at Christmas. When we got older Dad sold the American Flyer and bought a bunch of Tyco HO gauge stuff, still Christmas only. Dad gave the Tyco stuff away after I moved out of the house.
After I got married I didn't have much room for a layout so I decided to give N gauge a try. I put together a couple of layouts, but after a few years I lost interest and sold everything.
I still love anything having to do with trains and railroads.
Occasionally I will pull over to the side of the road to watch a 5-engine consist roll by (there isn't much freight activity here on the San Francisco Peninsula, so when we travel I relish the opportunities). My wife thinks I'm nuts but is used to it now.
Who knows, maybe after retirement I'll dive back into it.