Use your money to buy various upgrades in the game, including more trains and tracks. In the research section, you can generate research points. Use those to buy more upgrades for your trains and unlock even better trains. The key to success in this game is good management; you need to keep to the supply chain healthy and earn steady revenues over time. Remember that your trains need to be serviced regularly. Rail Nation has 6 different eras, you need to do your best to be the most developed city.Tip: Try to finish the tutorial and do the tasks to earn rewards and know the game's mechanics.