i have an HO gauge Lionel train set that was my parents when I was little.  We'd put it up under the Christmas tree every year & my dad & I would make Lincoln Log houses & play with the train.  I need to get a new transformer for it.  When I plug it into the wall it just starts to smell hot.  

When my youngest son was probably about 8 I bought him a train from Sears that was fairly kid-friendly. When he got a few more years older, I bought a smaller, more detailed train.  Don't know the gauge but it's definitely abut 1/2 the size of my Lionel train.  

Finally, I still have to TONS of the wooden Thomas the Tank Engine trains, tracks, buildings, & accessories gathered over 4 kids.  

When I was 7, my Dad got me an HO gauge Lionel train for Christmas. He mounted it on this large board with switch tracks and a pass over bridge. He also put screws in the roof of my bedroom so that I could lower it from the roof when I wanted to play and then raise it back up to the roof when I didn't want to play. 

When I was 12, he got me an N gauge with lots of tracks but we never mounted that one. I did however, run it from one room to another room all over the whole length of our house. But Mom wouldn't let me keep it running for more than just a few hours. Got in her way of cleaning and moving about the house. LOL

And then, when I was about 30 years old, a friend of mine received a Z gauge train from one of his customers but he didn't want it so he gave it to me.

When my kids were small, we got them a PlayRail plastic rail set (battery operated) and an electric car circuit for them to play with.

About 8 years ago, my Dad packed up all the HO gauge and N gauge trains I played with and sent them to me. So now I have all of them, but no place to set them up. (* CHUCKLE *) Well, actually the Z gauge is so small I guess I could set it up, but just haven't had the time. One of those "TO DO" things that's still not completed. LOL

FWIW

I’m envious of both of you. I was deprived.  We had a set but it wasn’t one of those.

Here are pictures of my Z gauge...

To give you an idea of how tiny they are:

It's so hard to get all the wheels on the track because it's so small, you really need to use this tool...

My dad's cousin, when they retired to Florida set up a train going around his front yard.  It was pretty good sized. 

They probably have a G (Garden) scale train...

FWIW

That would be fun to watch.