After the update, the Talent 2 on the Rapid Transit route has lost almost all of its sound. I checked the Talent 2 on Köln-Aachen and it's not my sound system. The "improved" sound on RT is almost non-existent. There's dead silence in there, only the switches can be heard. No running noise, no wind, no fan sound (which is probably the most dominant sound on Köln-Aachen), nothing. The exterior sound is fine, but since the windows can't be opened on the Talent 2 almost nothing can be heard inside. Just compare it to the Talent 2 on Köln-Aachen to hear the difference. I hope it's just a bug you can fix and not a deliberate sound mix.
Same on PS4 Pro. I can hear some track clickity clack but not rolling wheel sound or something that indicates the train is moving.
+1 The traction motors can now be heard and seem to be at a good level, but no track noise at all is quite a big immersion breaker.