When you track your current path on the map you will notice that it has a trend. The exact way you can tell from a short section of rails the direction they are heading. If you tell the truth, where that path is heading is not where you want to go... So what is there to do to change your future?
Let's use the map of the United States for the sake of the visuals among you.
If you want to build a railroad from where you are to let's say Seattle, what are the important things you need to know?
Where exactly are you?
What is the terrain like between where you are and Seattle?
What are the means that you can use to build your rail?