I have encountered the same issue with railroads in Green Valley. My train bridges got broken after the last game update. I have reported the issue to the helpdesk/customer service but they did not help (basically I was asked to rebuild the railroads again despite me saying that the railroads would not connect anymore).
The only way I found to get my train stations to work again was to connect each of them to themselves. (Kinda stupid but better than nothing. At least I can still dispatch trains efficiently).
I am waiting for the bugs to be fixed and have left the required space for railroads to connect once the issue is resolved.