I don't know what happened, but as soon as I start running it, it will load for a few seconds, and then stop, with no error message. 32 bits run ok.
^ Usually it's due to some faulty scenario, that's what the game crawls (collects) at the beginning. Although, if it starts in 32 bit, it could be something else. Resolution: Post your complaint in the Technical Reports and maybe one of the ongoing announcement threads. (Seriously, this issue is ongoing for 8 years, it needs to have some priority. At the very least, ignore faulty files gracefully.) Clear your cache. If you can't start the game, just delete .../RailWorks/Content/SDBCache.* Start the game, it will take a while to rebuild. Sometimes it succeeds and starts 1-2-3 times until corruption. Search for ScenarioProperties.xml, sort by recently updated, peek inside and whenever you find a faulty one, delete its entire folder. Try to start the game, clear cache if it fails. Repeat. Delete every Scenarios folder inside Content (inside routes). You can restore official scenarios with a Steam file integrity check. You can also rename them to Scenarios.bak each. Start the game, repeat the above as necessary. Unsubscribe from all workshop (favorite instead) and repeat the above as necessary. Reinstall the game. Guess we should have a sticky with one of these lists perfected. Silly me types it each time, but I'm well into double digits and I'm not the only one!
Thanks to those of you that replied. I have not installed any Workshop Scenarios or assets. The last thing that has been installed, was the update to Train Simulator Classic. I hadn't run it for about 10 days. It was ok then. When I get time later, I will try triznya.andras list of possible Resolutions. Again, thanks 749006 and triznya.andras.