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.
Coins
Use the "Bank" option from the in-game menu to exchange Bux into coins. The exchange rate changes each day. Check the rates for several days in a row to learn what the best values are. Spend Bux to build trains, even if they are not needed. You can sell those trains for a lot of coins.
Easy money
Spend Bux to build trains, even if they are not needed. You can sell those trains for a lot of money.
Getting Bux
Watch the game while your trips are in progress to have a chance of receiving gifts, which include Bux. Watch the ad videos to earn free Bux. During levels 3 and 4, there are lots of opportunities to make trips to earn Bux. Tap the "Free Bux" button in the shop. You can earn 2 Bux for each advertising video that you watch. Play often to keep the trains moving. Most of the stations are close one to another, requiring about five minutes to reach their destinations. As long as your trains are moving, they are earning money. Do not spend Bux to refuel. Every minute of waiting costs 1 Bux. It is better to let the fuel tanks refill without paying. They do not have to be full to make the new trip; you only need the minimum amount. Play the daily event which usually requires you to deliver a specific number of crates to the destination marked by a golden exclamation mark on your map. When completed, you can earn free Bux and train cars.
Licenses
Buying new licenses to access new continents does not have to be done before you fully cover the ones that you already own. A good first license to purchase is America, followed by Asia. If you purchase them too soon you will not have money to take advantage of them.
Train cars
Whenever you see a car that offers Bux or Train Pieces, deliver them as fast as possible. The value that you get from exchanging Bux carts for coins at the bank will usually exceed any value you can get from regular coin carts. The Train Pieces are needed for building new trains (engines) or fuel carts for trains. Although you will want to have as many trains running as possible at first, having no fuel in the tanks will require longer waits and cause a loss in revenue. After you have five trains running, build fuel cars for them to keep them running longer.
Building routes...