What do I collect? Candidly at my age the answer might be "Dust"! However, I just really love the O Gauge and Std Gauge tinplate. Mostly American mfrs Lionel, American Flyer (pre-war O), Marx, Hafner, etc. I admit a weakness for the colorful painted and lithographed cars mostly of the "prewar" era. Although the Marx, low cost trains in both tinplate and plastic are just too much fun to pass up and they are both normally inexpensive and the engines almost always run. However this is mostly for "shelf stock". For operations, I usually go to the Lionel and Marx post war / Lionel modern, MTH and some K-line as they are more reliable "runners" and parts can be found for them if needed. I admit to stopping short of much of the new "electronics" and "command systems" as candidly I don't understand how to wire them up or use them. I could learn but have not really wanted to bother. My layout is ZW powered, star wired, and block controlled by toggle switches. Just like my Dad taught me to do in the 50's (we had trains from 1947 on but being born in '44 for much of the earlier periods I just watched ! ). Dad was senior at the company where he worked and got 3 weeks vacation while Mom who worked for the same company only got 2. So Dad would take that 3rd week post Thanksgiving to set up the trains. I would come home after school every day to help and learn.
Like many families in those days, although our layout was quite substantial for the time (by '53-60 covering 1/2 the basement) it went up after Thanksgiving and came down in Mid January with the trains all packed up and put back in the attic.
I have two more "branches to my "collection".
The first comes from the fact that I worked for the Dept of Defense (AF and Navy) in Engineering for 35 years and got sent overseas (Europe, Scandinavia, Asia) for regular field trips to our and our Allies a/c maintenance facilities when technical help was needed or to provide training to on-site folks. Whenever I traveled to a foreign area I tried in my off hrs to get some piece of train related items, usually modest in price. So I have a very eclectic mixed collection of foreign trains / stations etc that really are more of a memory collection than anything else. I have German trains from Marklin, Wimmer, Dressler, Bub, and Distler, UK trains from Hornby (Mecanno), Chad Valley, English Marx, a few scattered freight cars from Denmark and Norway, and lots of Japanese litho tin stuff (this stuff is just great in terms of color and quality). Due to more recent travels related to my later career I also have two full sets, in the box, of litho/plastic trains (about S gauge size) from Korea - one clockwork and one battery.
The second "branch" of my collection involves floor toys, all trains or train related. Mostly lithographed tin and they come from Japan, US (mostly Marx), UK (including English Marx) and some other countries. These do not run on tracks but they make up for it with noise, music, animation, sparks, and various fantasy components (like a big Monkey as an Engineer) etc. They are a hoot to watch and mine mostly all work as I bought them new.
So JD is right, I guess we are all different and collect various things that make us smile.
Don