The rule is simple, at the beginning of the new game, three stations (nodes) will be serve as starters. You have to connect them to make a train network. Once the line has been drawn out, a train will start its operation.
Source : Greater Washington
However, as the time pass by, the number of stations will increase on the map, thus requires more rail line to be drawn to connect those stations. There are three types of stations, which can be seen by their shape (squares, circles & triangles - employment centres, residential areas and community facilities respectively).
The challenge here is to minimize the waiting time for passengers at each station since each line can be used by only one train.
The game is considered over when too many waiting passengers build up at station.
Suitable for Who?
The game concept is like Sim City where it requires you to manage a growing town or city. In this case, this game requires you to manage a subway network. Well, this game is suitable for all ages, especially rail enthusiasts or someone who wants to test their transit planning skills.
Come give a try
You can read further about this game in here and here . Feedbacks from users of this game can be read here.