Hi Terry
Please ensure that you have not turned down, or muted, the sound in the Windows Sound Mixer. This is accessed by right clicking on the speaker icon, then click on 'Open volume mixer'. Note, to be able to see/adjust Trainz, you will need at least the Trainz launcher open.
Please also check the volume within Trainz, which you can access by following these steps:
1) Double click on the Trainz desktop icon
2) Click on Start Trainz
3) Click on the 'system menu' button at the top left (looks like 3 horizontal bars)
4) Click on Settings
5) Click on the 'sound settings' option in the left hand menu
6) Ensure that the volume slider is set to a suitable level
Regards