18OE: On the Rails of the Orient Express is a monster 18xx game covering the entire European continent. There are five types of companies - Private, Minor, Regional, Major, and National.

As in every 18xx game players invest in railway companies by buying stock, with the majority stock holder of each company deciding how the company acts on the game board. Depending on companies' actions the value of stock changes, and players might receive dividends for stock held. The winner is the person with the most money after adding the value of his stock holdings.

This game is notable for its size, that it is rivaled only by 18C2C. The focus of the game is making the Orient Express run - having a train travel from one of the western capital cities to Constantinople.

While the full game takes 12 hours to play, shorter scenarios are included that take 4 and 6 hours each.