Board Thread:Questions and Answers/@comment-25337628-20140822235203/@comment-15636815-20140910072119

You control the contractor's station, and you have full control over everything that affects the station. That means you can buy buildings with materials on hand, move buildings, store buildings, and sell buildings. All of the same applies to decorations.

You do not control the trains leaving the contractor's station. (Hey, they trust you, but not THAT much!) You can send more materials to the contractor, but you can't load a train at his/her station to send materials back to yourself. Therefore, the statement that you don't control a thing is completely untrue, even though you don't control the one thing that you appear to believe is the most important. ;-)