Railroad Tycoon 3
The simplest of ideas work well here; you receive a briefing on how to achieve a gold, silver or bronze medal and then it's up to you to become a railroad tycoon!
As soon as you have overcome the learning curve (recommended you take the tutorial) it's easy. The stock market is also involved but it's not essential that you understand this.
This game isn't just for train enthusiasts either. Anyone who enjoys management games will love this! You can also control various other businesses including steel mills, taverns, farms e.t.c. You get the picture. This, is of course after you have named your company and chosen a logo.
Some campaigns see you purchasing access rights for different states (I tried to buy the whole of Germany), other see you going head to head with other tycoons.
The graphics are OK but gameplay is important and it definitely delivers on this. The replay value is brilliant as well, with a multiplayer mode and different medals to achieve.