We were fascinated, because the same thing occurred near most every town along the way. Each plot was interesting, but they went by so quickly we could hardly point em out to each other. Why along the tracks? Why so many of them? They were typically German (to us)--very orderly, all of it done with great attention to detail, and property lines, and with humor. (You can tell the Google photo, above, is taken from the height of a train).
So, when we got home, I looked it up:
"Most Germans may live in cities, but they still remain attached to nature. That’s why those who can’t afford their own house and garden often have a small allotment, enabling them to get away from the hustle and bustle of their daily lives and work. Generally located on the outskirts of cities, these allotment gardens are grouped into so-called “colonies”.Read the rest of the explanation at the link--it's pretty cool and very German ☺