Apologies if this has been raised before - these forums have so many entries it would take ages to check them all. I have been playing train sims since the original MS Train Sim way back when, and bought the new ones as they have come out. Something I have noticed with TSW, TSW2 and TSW3 is the audio is missing elements. This is mainly the change in sound when going into and out of tunnels and passing under bridges. Even in what is now called Train Sim Classic, I can hear the "whoosh" as you pass under a bridge, or the echoing sound when entering a tunnel or something like a brick-lined cutting. I don't hear this in any of the TSW variants. Maybe the cabs of modern stock are well sound-proofed but I doubt they would kill the noise completely, and older stock I am sure wouldn't. Even with windows open there is no appreciable change. The same applies to the sound of passing trains - you rarely if ever hear anything. I have played with audio settings but can't seem to make any difference. Is this a deliberate thing, or am I missing something?
Are the sounds you're hearing on TSC content specfically DTg content, with no other packs or EPs installed? Much of the enhancements in TSC come from additional packs rather than the default and in TSW all you have is the default... Whether you think that's deliberate or not I'll leave up to you
Sadly that's a core shortcoming of TSW that still hasn't been fixed. The first TSW route didn't even have darkness in the tunnels... Some routes to have sound reverb in tunnels and certain areas like under big station roofs, but it is not implemented in most places. It's funny when decade old train simulators do it, but not TSW.
Tunnel reverb was in tsw2020 but has been removed since. The reason dtg had back then was that reverb was causing sound problems so it was left out. So they decided to remove it. Don't know if it'll ever be possible
