Melvin, I like your philosophy of keeping and running trains.
I sold all my PS1 and other non-command engines in the early 2000's. Most of them were traditional size. MTH re-issued all of them, I believe with PS2. My decision to sell at that time was due to going full command control (TMCC and DCS), moving towards scale trains, and aggravation of engines getting locked in neutral from drained battery.
Another category that MTH variety shined with numerous models were the die-cast streamliners from the 1930s. I recall seeing quite a lot of these in catalogs over the years.