ok, i deleted following folders:
/Users/XXXXX/Library/Application Support/Steam/SteamApps/Train Fever
/Users/XXXXX/Library/Application Support/Steam/userdata/XXXXXXXXX/304730
and all of its contents, the i downloaded TF again via Steam, after installing i closed Steam Client, restarted Steam Client and clicked “play” within the steam client.
–> wokred now!!!! yeah!!!!
… works also now with the desktop shortcut!!!
maybe this info will help someone!
thank you!