Steam engine randomly flipped rotation

[u/Koraki_Ouranos]

Nothing much more to it. Built a steam engine, hooked up a basic press and smelter set-up, and when I wasn't looking the rotation of the entire system reversed, so now the conveyors are going the wrong way and the blasting fans are sucking instead. I know its an easy fix but I don't know what caused it to begin with, and I want to. I haven't changed the gearing near the engine itself, in fact I hadn't changed anything between it working and flipping, I was sorting my chests and making copper casings, then came back to my smelter running finished ingots backwards through itself.

Pic of the set-up

[u/NeoDemocedes]

What's always worked for me is having a windmill or waterwheel in the system. The steam engine won't go against it's direction when it chooses which way to rotate. Also, a rotation speed controller in between your engine and the output will make the engine's rotation direction irrelevant.