Good Afternoon Bob
At this stage I believe this update is still in beta, so you will need to change your patch stream to the 'Trainz Plus Beta' stream to access this update.
You can do this by following these steps:
1) Double click on the TRS19 icon on your desktop
2) Click on Trainz Settings
3) Click on the 'Install' tab
4) Click on 'Change Trainz update stream'
5) Follow the prompts till you see the 'change update stream' option, then click on this
6) Click on the drop down list, and click on 'Trainz Plus Beta', then click on 'ok' and 'done'.
7) Now click on 'check for Trainz updates', and follow the prompts to install the available update.
Regards