1865 Sardinia is a board game belonging to the 18xx series for 2-4 players and set on the Sardinia island (and Corsica).

Players play the role of 19th century entrepreneurs investing in the construction as well as the financial and operational management of railways. Selling and buying shares on the stock market, seeking new sources of funding, laying track and placing stations, running trains and paying dividends are all basic elements of 18xx games.

In addition, 1865 Sardinia has several features that make it different from other 18xx titles. The most important distinctions are:

a traffic based system that makes calculating company's revenues easier and faster
foreign investors (Dragons) trade in certificates in addition to human players
an absorption mechanism that allows companies to acquire each other

Other interesting points:

before phase 5, all companies start as minor companies with 40%/20%/20%/20% shares
converting a company from minor to major requires a direct route from a company base to a historical destination city
private companies become 2 trains when transferred to a company and also provide extra traffic
buying trains from bank makes the share price jump up
the last 2, 3, and 4 train comes with a discount
withholding money in company doesn't reduce the share price
tiles can be replaced with another tile of same color, provided the current connections are retained
bankrupt players are given enough loans to keep them in game, loans are then deducted from final score in the end

Dragons

during stock rounds, the Dragons will also trade
each stock round begins with a Dragon and Dragons also play between each player
dragons are interested in company's rank, an indicator based on the sum of trains phase and tokens on board, followed on a special table on the board
dragons will immediately sell certificates in companies ranked red and will buy certificates ranked green, according to a fairly simple and consistent algorithm.
players can buy shares from Dragons, but must pay a premium for well-ranked shares
share prices are adjusted down when shares are sold by Dragons or the company president

Traffic system

when a company places a station marker, it gets to collect traffic chips from the board along the route
mines also produce traffic chips, but diminish in value as the game proceeds
each traffic chip is worth $10 in revenue
revenues are the smaller value of total revenue in traffic chips and train capacity available
phase 2 trains, for example, have 8 capacity each, so if company has two of those for 16 capacity and 14 traffic chips, it will make $140 in revenue, while adding three chips would increase the revenue to $160 because the capacity hits the roof at that point

18MEX