Simcity regional freight shipping
I have a commercial city with no industry and there are ~5000 unfulfilled freight orders. The amount of freight commuting in fluctuates between 1000 to 4000 but never enough to satisfy all 5000 unfulfilled freight.
How do I get more freight to "commute in"?
Things I have tried:
Building a trade depot/port in my commercial city: This causes MORE unfulfilled freight orders since the trade depot/port expects freight shipments from local industries.
Building an industrial city next door that has excess freight: My industrial city has about 2000 freight "commuting out" yet it doesn't seem to have a significant effect on my commercial city. When I look at the freight view from region view, it says my industrial city still has a fair amount of unfulfilled freight orders even though it is already shipping out 2000 in excess (I have no idea what is going on here).
Each building which has freight orders sends out invisible agents looking for sources of freight. Those agents are absorbed into the sources and let the source know where the freight should go.
There are two waves. The first wave looks for freight in the city - from industrial buildings, only. If there are remaining unfilled orders, the second wave looks for freight out in the region.
Like many regional resources (power, water, sewage), unfilled freight orders may be divided between neighbors. So if you have 5000 unfilled orders and 4 neighbors, each neighbor could supply, at most, 1250 freight.
Reconsider why you want to fill those orders. Unfilled orders are usually just a growth opportunity for cities. If your commercial buildings are abandoning with the reason "need more freight", they are actually just running out of money and blaming freight. They would not run out of money if they sold all their goods. Check the commercial dataview at 5 AM each day and reduce commercial in areas with unsold goods at that time.