When i play TS the volume is very quiet and my volume is set to full. Does anyone know why the volume is so quiet even though its on full volume??
Check the sound volume settings in three places. #1 in Train Simulator by clicking the Settings button, then Audio, and checking that both the Ambient and Master controls are turned up #2 in Windows, usually clicking the speaker on the tool bar #3 for your speakers if they have a volume control (I can't count the number of times someone has turned it down on me)
I notice this quietness, especially with AP stock, too. But I forgot to check number one in your list above, must do so tomorrow!
In Windows it's possible to mess up per-app volume, so you could have 100% system volume but your browser would be 50%, music player 30% and your game 20%. Changing system to 50% would also move individual apps, keeping their percentages. The easiest mistake is to raise the volume of just one app, which will effectively raise master, keep 100% on that app and proportionally reduce the rest to keep them at their previous master. Note the horizontal line connecting from the overall volume. It's a major pain in the butt to fix if all you want is 100% for all apps. The easiest way is to set everything to 100% and then reset master to whichever you desire.