Sound levels in TSW 3 are still not right. External sounds of trains are way too low, unless within a few feet of them, you cannot hear them very well. Whenever you watch real trains arriving at or departing stations, or see them rushing past, they make a din, yet in game, the ambient sounds can often be louder. The voiceovers on the routes are also too quiet. Just did the SoS route intro and I could barely hear the scousers dulcet tones he was so quiet. A lot more work needs to be done to balance the sounds correctly and to make them more substantial where appropriate.
Perhaps there will be a patch for this soon. I don't think this was an issue for tsw2 so I don't think it will be difficult for dtg to fix
