From what i remember its the issue with GPU drivers. I had the same issue but after reinstalling the system it "fixed" itself.
You may try that solution. Sometimes the sky and sun was so bright that it was almost impossible to see lights or even tracks 😅
Bolączka Simrail'a niestety.
Na szlaku jak i na przystankach jest totalna cisza. Słychać tylko "Gotów do odjazdu".
Bardzo dużym plusem było by dodanie właśnie rozmów innych składów z dyżurnymi.