Not for all to understand but I am making note.
Ever since TS2014, I have to use the "SET LAUNCH OPTIONS" -ShowSoundDeviceSelector which allows choice of system sound device.
I use a Creative Sound blaster card with 5.1 surround and it's the only way I can get surround sound playing the game.
Start the game, the screen goes blank, hit your Win/Start key on keyboard, you will see a select sound window on desktop, then I select Creative, hit OK, back to game. I now have surround sound when playing. Pain in the 'you know what' but got use to doing it and it works well and I got to have my surround sound!
I found no other way to do it.
P.S.
Used to have a OpenAL32.dll in the main RailWorks folder with the 2014 update. It was still there after the 2015 update. I would have some of my sound quit during game play. Like engine idle disappear or wagon sounds disappear randomly. For the heck of it I moved the OpenAL32.dll file out of the RailWorks folder and I have no sound issues at all. I still have to start game as described above for surround sound.
Just wanted to make note about the OpenAL32.dll file that I don't think we need.
Win 7 Pro 64
AMD x4 3.5 GHz
8 gig DDR3 RAM
GTX 750 Ti OC