Cities also have demands and you must have them in mind when you connect industries to them because if you are trying to deliver more than city needs 2 things can happen:
a. connection from new factory won’t produce because the other factory fullfills all demands from city
or
b. newly connected factory will be more attractive for town and it will take away all the demand from the previous one effectively killing earlier route.
Remember, industries are always competing with each other for city demands in this game.
