The central hub for downloading mods is the Steam Workshop.
Login to Steam in a browser or your Steam Client, navigate to the workshop and subscribe to mod. The mod will be automatically downloaded.
Mods can also be found on various fan sites. Two great sites are http://www.transportfever.net/ (English and German) and http://transport-games.ru (Russian). At these sites you can look for mods and typically download mods as (zip) archives.
Just extract the (zip) archive into the Transport Fever mod folder which usually is located in the game installation folder. Find out more about folder locations here. Make sure that the mod has its own folder inside the “..\mods” folder (usually the zip archive already contains this folder).
Start Transport Fever and go to the “free game” page. Select “Custom” and switch to the “Advanced” tab and there you should see the installed mods. To enable a mod, double click it or click the grey switch in the “Enabled” column. It will turn green if a mod is enabled.
After starting the game, the active mods will then be “coupled” to the game. If you save and reload the game later the active mods will automatically be enabled again.
It’s also possible to add mods to existing saved games (enable additional mods for a saved game).
Warning: Because some mods modify game resources in a critical way, doing this can lead to unexpected behavior or even game crashes. Nevertheless, adding mods to existing save games is needed in some cases.
To add a mod to an existing saved game, go to the load game screen. Select the saved game you wish to start with and click on the plus “+” sign in the mods area at the bottom of the screen.
If you are interested in developing and sharing your own mods, please have a look at our Modding developer information