Is this when you load the game or a particular route? Do you have any mods installed which may not be TSW4 compatible?
That may be so, but jack has asked for whether the game freezes when loading the game itself, or when trying to load a route (after navigating the menus). He has also asked for whether you have downloaded any unofficial 3rd party mods, not routes. I would also like to ask if you have any engine ini tweaks or are forcing -DX12 through Steam. If you have no idea what any of that means, then you needn't worry.