Why factories don't order ahead and from nearest supplier? I have constant troubles with factories in this game. I've set up only one factory and it lacks resources most of the time.
I did set up every storage building on fill so it doesn't export outside of the city, but it doesn't help. I have usage of trucks between 0 and 3 for storage buildings.
As an experiment I cut off access to the rest of the world and it worked perfectly - just before factory ran out of supplies, there was delivery and I newer saw any problem with resources.