A file for Train Sim World 3 typically indicates a compressed archive containing game data, such as a manual installation of the game, specific mods, or community-created assets. Important Consideration: Security and Legality
For Steam users, this is typically: \SteamLibrary\steamapps\common\Train Sim World 3 . Train Sim World 3.rar
Use software like WinRAR or 7-Zip to open the archive. A file for Train Sim World 3 typically