I’ve found that an important first step in understanding an analtyics or optimization problem is to visualize its scope and try to make the numbers meaningful.

I was researching the coal industry to get some realistic numbers for a case study in our new book, Supply Chain Network Design.  It turns out that the US mining industry pulls slightly over 1 billion short tons of coal out of the earth in 2010.  A short ton is 2,000 pounds.

Well, 1 billion is large number, but I wasn’t sure how large.

Here are my top 5 ways to visualize (without graphing) 1 billion tons of coal:

  1. 10,800,000 rail cars. Still a large number.  Not sure this helps, but this allows us to start to understand the logistics in moving the coal from the mines to consumption points.
  2. 297 unit trains per day, every day.  A unit train is a typical coal train with about 100 cars.  That is a lot of trains, but a number we can start to visualize.
  3. 5 1/2 hours per day watching unit trains roll by.   So, if you are stopped at a RR Crossing and those 297 unit trains start rolling by, it would take 5 1/2 hours for those trains to roll by.  Since a unit train is about 1 mile, another way to think about this one is that this train would stretch from the top of Indiana to the bottom along I-65 (actually it would be little longer than this, but this is close).
  4. 260 Louisiana Superdomes.   If we put all the coal into the Louisiana Superdome, we would need 260 of those structures.  This converts the coal to space verses a rail car.
  5. A 5x5x5 box of coal for every person in the US.  Before I did this, I would haven’t been able to say whether the coal burned per person would fill up a box, a room, or a house.  A box about 5 feet by 5 by 5 is a big box, but just a box.  (Remember, if you have a family of 4, you need four of these boxes).