Set up train routes that travel in a straight line towards one connecting city. For example, use Paris as a connecting city at the start of the game. Build five or six lines that all end at Paris. Then, upgrade the Paris station to hold as much cargo as possible. Create routes no longer than four or five cities in length. Line longer than that will become too difficult to handle. There will be too many goods for your trains to transport and you will have them stuck in yards and train stations. By using shorter routes your trains will always quickly reach their destinations packed, and earn more money. Instead of filling your train in your city and delivering three or four train stations away, it is better to plan your routes from one station to another. By doing this, when you arrive at a new station you will have the option to add some extra cars to your train and increase your pay.