Dont use the Full Loading Option the game is not able to handle it. Sooner or later itscausing big Problems. For example using 1 Line to Transport coal and iron with the otpion loading full causes a drop down in productin rate from 120 to 1. If you use full load the production line brokes down. Just use laoding when cargo is waiting and try to use so many trucks Trains or whatever that there is not to much cargo waiting.