First, the order seems not optimal to me. You are trying to ship iron ore via the far away coal mine to the steel mill. The iron ore is faster by foot going immediately to the steel mill by itself. So the pickup order should better be 1.Coal, 2.Ore, 3. Goods, 4. City.
Secondly, I would not ship the iron ore. It’s close enough to go by itself to the steel mill. Take care of the coal and goods only. It’s easier to manage.