Easy fix while you optimize production, set up pumps to limit oil flow to the refineries that are producing the petroleum gas. Connect them to your storage tanks with red or green wire and set the true condition to be: oil less than 20 000k.

I have the same passenger train network. It's the human way to travel. Try this, set wait state to "passenger present" AND "passenger not present" at all stations for your passenger train. That way, the train will always wait for your intructions before moving. You can have it pi...