I recently bought TSW4, along with the CN Oakville Subdivision DLC. A few day later, I also purchased the Horseshoe Curve DLC. Unfortunately, after playing Horseshoe Curve once, the CN Oakville Subdivision DLC has disappeared. No matter whether I start TSW directly or through Steam, the only content I see is the Horseshoe Curve and its locomotives. Nothing else. Has anyone else experienced their content disappearing after purchasing new content? If so, how can the previously purchased content be made to reappear?
I think I found the answer to my own question: In the Steam portal, there is a small DLC box at the right bottom. It has a link "Manage my DLC" in it, which shows the list of purchased DLC. I noticed that for some reason my CN Oakville DLC was unchecked there, so I checked it and it started to download that DLC. I'm not sure how it had been uninstalled in the first place. But it's back now.