For a while I would work as a coder during the day, and in the evening I would work in the mines, for my son. "Dad we need more iron ore. Dad, make sure the furnaces have coal in them." Eventually my kid worked out that you can build generators, effectively coding it in MC bricks and providing infinite resources. Probably the first time he's coded something, he just doesn't know it. This made my evenings a bit less m…
Minecarts really are useful only to transport creatures around, and to distribute stuff from and to furnaces.
But basically if you don't find enough iron in a given length of cave, you can't have tracks all the way.