How does 1-train/0-train work?

[grumble321]

I don't know if it is preferred that I start a new thread, or I revive a really old thread for this - please let me know.

The question refers to this thread:

(mods: if you'd rather merge this into that thread - by all means, please feel free to do so)

My question is that I don't really understand how 1-train or 0-train things work, or even exactly what they are. I'd be grateful if someone could explain.

thank you.

[Gwizz]

Locomotive did a good job in figuring out different methods of winning with less.

He would run a railroad with no locomotives or very few, using industry profit or merging railroads for profit, etc.

He could squeeze the dollars to maximize any gain. Using fewer locomotives caused lower expenses and often higher values for the cargo hauled.

He would make a good Railroad Tycoon for the late 1800s to the early 1900s.