Railroad Tycoon 3

Overview

Railroad Tycoon 3 puts you in charge of your own railroad empire.  While the first game in the series was called Sid Meier's Railroad Tycoon, the "Sid Meier" portion was dropped from the second and third installments in the series, but appears again in 2006's Sid Meier's Railroads! which is the first game in the series since the original 1990 game that Sid Meier had a hand in developing.  Railroad Tycoon is considered by many to be the definitive "tycoon" series, and indeed seems to have been the first series of this sort to have the world "tycoon" in the name.

Almost superficially a game about trains, Railroad Tycoon 3 is really about running a business and, in some cases, running your opponents out of business.  Trains are used to deliver mail, passengers, and troops (all of which have specific destinations), and to deliver various freight, which your company earns money for based on the difference in price between the pickup location and wherever you choose to deliver them to.     
  
All of the goods for delivery are created at businesses that you may purchase or, in some cases, build.  Secondary and tertiary industries are dependent upon goods from other businesses to produce anything.   For example, alcohol tends to be in high demand on most maps, but a brewery does you no good if it's not being supplied with grain.   As the area surrounding the brewery runs low on grain, the price will increase.  This will make it more profitable to deliver grain to the brewery.  If your company also owns the brewery, it will benefit from any money that brewery makes (cost of finished good - cost of input - cost of labor).  In this way, the player manages not just the link between industries but also what goods are created, in fact what routes become profitable. 

Objective

Featuring a campaign that is actually quite varied, objectives can range from something as simple as getting your company to a certain value to delivering particular numbers of particular goods while acquiring a certain amount of personal wealth (as opposed to company wealth), although the means to get there is nearly always to make your company as profitable as possible as quickly as possible.  There are also scenarios involving scheduling of trains; the stations and trains are all pre-built and your task is to send the trains to the right stations in the right order to deliver of specific goods or earn enough profit.
 
Using the stock market can be important in some scenarios, whereas in others you might not have to concern yourself with it at all.   In scenarios with personal wealth requirements, you can trade shares of your or other companies (even on margin), thereby increasing your net worth much quicker than simply via the salary as CEO of the company.
 
There are three levels of completion for each campaign mission: bronze, silver, and gold.  There is also a sandbox mode where no money is involved and a multiplayer mode where the goal is to buy out all of your opponents' companies.  The game seems to have been designed first and foremost as a single player game, however.