Make sure your trade depot is both close to the factories and as close to the city entrance as possible. You want to try to eliminate any traffic issues for delivery trucks. Max out the delivery trucks for the trade depot. Instead of plopping more storage warehouses on your trade depot, plop another full trade depot so you can max out another 4 delivery trucks. Once your Omega production gets going and you're able to keep up with the demand for resources, it will really start to pay off.
This video from Skye Storme's Let's Play Series shows the bug and how he deals with it. There is so much information in this LP series, I highly recommend it. His complete Omega city build starts with Episode #36 with a blank region and covers the basics to optimize a full Omega city. Even if you're not interested in building a full city of Omega, the tips about transportation, medical, fire, and using medium density low wealth buildings is invaluable.
Good luck on your Omega factory! Once I got the hang of it, I really enjoy building filthy polluted cash cow cities 
Let us know how yours goes. Happy Building!