Install:
Extact the downloaded ZIP-file in Train Sim World 2's DLC-Folder at [STEAM LIBARARY FOLDER]\steamapps\common\Train Sim World 2\WindowsNoEditor\TS2Prototype\Content\DLC\

Uninstall:
Delete the "TS2Prototype-IOWRouteImgFix.pak" from Train Sim World 2's DLC-Folder