So basiclly, after all this hogwash and name calling and telling me to get off of your Strategy forum, the simple answer was in the Wiki, made by Red Knight, which you brought up, which you had access to and all it was was an Industry grows based on the number of carloads moved in and out of said Industry. And since both the Power Plant and the Steel Mill are getting the same number of cars coming in (unless some of the trains contain an odd number of cars) the Steel Mill will grow faster than the Power Plant.
Huh, hours of testing and only 5 minutes was needed to find the information where you knew it was.
There is something you don't know O' Thee Of All Knowledge Great And Small!, many of us have a pet name for you.....
Hemiroid! You were given that name for one reason and one reason only....
YOU'RE A COMPLETE AND UNDENIABLE PAIN IN THE ASS!
I'm correct 97% of the time..... who cares about the other 4%....