Trains on stamps, Part 1: Stamps from Cuba, and one from Nicaragua. From my Showcase Collection (not Specialized Collection)

For me, the best way to enjoy collecting stamps (for educational purposes, not as a financial investment), is by creating a Showcase Collection: at least one stamp (simple, or on cover, or maximum card, etc.) from EVERY subject, theme, topic that interests me or others.

Why a Showcase Collection? 

"For the love of the game"...to promote this hobby - philately. Promoting online and offline.

I also have Specialized Collections, such as "Wild mammals on maximum cards".

For example, I'm not interested in yachting, but I'll keep at least one such stamp, for educational/illustrative purposes.

I'm not saying that I BUY all those stamps: some come free (not "for free" - pleonasm) from various sources.

So I am not spending much, even for those that I buy.

In fact, nowadays I mainly buy maximum cards - on the rare occasions when I buy anything.

Many of the stamps from my Showcase Collection are inexpensive CTOs (cancelled-to-order, valuing at about 25% of a mint stamp), from the days of my youth in Romania.

I am mildly interested in trains on stamps, but I kept a few of those that crossed my path.

In the above image from my stock book of stamps, notice a "stamps on stamps" series. In the lower left corner, there's a depiction of a stamp from the series exemplified by a stamp from that original series.

See that?