Man! This question has made me go back over almost my entire 67 years for the answer & It's a bit convoulted.
First off I have been a model builder since my first attempt at 5 or 6. I tried to build a 10cent comet Airplane kit -- an Eracoupe. I never finished it mostly because I was trying to cut the parts out of the printed Balsa sheet with the only razor blade I had access to, my dads DOUBLE edged Gillette!
The first thing I built for a train was when I was about 7 & had a Marx train set -- Lionel was too expensive for us, I had a Lionel catalog tho!
In that catalog were two things I thought were pretty spiffy an airport beacon with a rotating lens on top of a light bulb, the other was a Crane mounted on a swivel pedestal , couldn't get anyone to buy them for me so I built copies of them both in balsa , some from the ill fated Comet Kit, by now I had found out about single edged blades.
When I was about 8 we moved & the train got left behind. I moved from that into Balsa airplanes , loved the old Monogram Speedebuilts did all of them, then came freeflight , control line & RC. Somewhere about 57 or so Plastic car kits began to appear , now I never liked plastic airplanes , but cars were different, I tried a wood car kit once --- what a mess even well done they did not look good! So I pretty well ended up building 1/25 cars -- mostly hot rods & customs , along with a few RC planes. Still I felt something was missing- I saw many things in everyday life that begged to be modeled but , what would I do with it -- didn't fit with the cars or the planes soooo.
By now I'm 40 something & have a son coming up on 7 at Christmas, my wife decided that he had to have a train set, off I go to Grand Central stores ( remember them?--- a 70's walmart) They have a sale on TYCO stuff ( Mantua) I went nuts cause it was 75 % off or something like that. So I get a potfull 6-8 steam locos --some War Bonnets-- a raft of rolling stock & all that goes with it.
Turned out my son had less than zero interest in trains so in the attic they went .
Cleaning out the attic a few years later I came across them & the LIGHT finally DAWNED , Model Railroading was THE PERFECT HOBBY for a guy that liked to build models!! Whereas with cars or airplanes that was about all you could do , BUT with trains ANYTHING you had a fancy to build could be part of the WHOLE !! I have never tired of it since then. Nice to have the whole world be your prototype.
Sorry this is so long but there it is.
Yes , I still have some of the Mantua steam ( tricked out , detailed & remotored ) but the rest has long since gone as I moved up in quality, & started Scratchbuilding my own models.