#7 - Railroad TycoonReleased 1990 for PC
Before Sid Meier brought us Civilization, he created Railroad Tycoon. This is basically a business simulation game, but with trains! Yes, it is as cool as it sounds. You basically start a railroad company from scratch (sometime in the 1800s), choosing where you want to lay track and build stations as well as purchasing trains and determining their consists and schedules. You start with $1M cash as capital that is 50% equity (from a stock sale) and 50% debt (bonds). As the game progresses, you have the option of selling more stock, buying back stock for treasury, or selling/repaying bonds. You can even buy stock in rival railroads, and if you eventually buy enough, you sit on their board and make decisions as a controlling interest.
You also get into the details of the railroad business as well as local economies. The game does a fair job of modelling supply and demand and has a very simple stock market consisting of the four competing railroad companies. As the years go by, the nation experiences recessions and booms which affect how you go about scheduling trains and how many cars to attach to each. Each town/city has it's own specific raw materials and plants, so it makes sense to carry coal from a coal producing city to another city in your railway that has a power plant. Or you want to deliver lumber to a paper mill. That city will then make paper which you can deliver to numerous cities and turn lots of profit. After you make enough cash, you can even build your own plants to process raw goods.
Depending on the difficulty settings you choose, you may find that a rival railroad has built track into one of your stations at which point you are competing with them in a rate war (you can also build track into competitors stations). After a certain amount of time, the cities council will vote on which railroad is serving the city better, forcing the loser to leave town.
Hotels, restaurants, post offices, engine maintenance shops and other improvements can be added to your stations. Of course, you have to way the cost against the potential profits (or cost savings) you would get from those additions.
Also wanted to mention that this was not the first business simulation game I ever played. That honor would go to the old Lemonade Stand game I used to play in the computer lab at my elementary school around 3rd grade or so. I'm pretty sure that would have been on an old Apple IIe I believe.