Simutrans offers the possibility to create scenarios: These are maps with preset goals and rules.
How to create a scenarioThe most difficult thing is to come up with an idea about a scenario - a vision what a scenario may look like. Then you have to cast this idea into a savegame. That is, create the world in which your scenario will live. Shape the landscape and build cities and factories. Now you are the ruler of this toy universe, you are in charge of the rules. These go into the script.
Scripting languageThe scripts have to be written in squirrel. The manual can be found at
Squirrel main page.
Example scriptsThere are two commented example scenario scripts at the
documentation page. Current versions of pak64 and pak128 come with a set of ready to use scenarios.
TranslationsScenario texts can be translated into any language. Any help is much appreciated!
Resourceshttp://scenarios.simutrans.com - download some scenarios there
http://dwachs.github.io/simutrans-sqapi-doc - the documentation of the interface to the scripting language
Helpin case you need some help do not hesitate to ask here in this forum.