you can basically delete them by turning off save game in the settings, then to make it work either leave your current session so the main menu doesn't show it or if you're in the main menu just load in anywhere and leave to go back to the main menu, then the save should be gone. you can then turn the setting back on if you want to save another time in the future.
If you are playing on PC, you can find the savegame files in the following directory: C:\Users\username\Documents\My Games\TrainSimWorld4\Saved\SaveGames Simply delete the files "PP_username.sav", "BAK_username.sav" & "TSWSaveGame_username.sav".