Ron - Changing water colour and surface conditions/ weather, fog levels and atmospherics is now easier - and more capable - in TRS19 than any previous version of Trainz.
You simply need to know that this is all done at the
Surveyor, Session Edit mode level - and that changes can be made - and saved - for any diurnal time slot you choose for each scenario you've created.
Look for the
Edit Environment... dialog, in the Session Edit menu bar.
The dialog has three main tabs on the left hand side, allowing access to different settings tools. (Lighting - Location - Environment).
Check out the Trainz Wiki for more information and "How to..." details here:
https://online.ts2009.com/mediaWiki/index.php/How_to_Use_Environment_Tools
There's a cool online, interactive tutorial on this process that was created by N3V a couple of years back. Will try to find the link for you and post it here.
https://n3vgames.typeform.com/to/y4J2Rl
In the meantime, please look for this dialog in the Edit... menu and invest some quality time learning how to master this amazing tool for creating realistic lighting and atmospherics for just about any scenario:
IMO there's a huge amount of misinformation and general confusion on these forums about lighting, setting gamma compression, and applying other atmospheric conditions in TRS19 that is utterly unwarranted.
Yes - we still cannot save our Post Processing settings to the session for future use, but we CAN set and save realistic lighting, water colour, set seasons, skybox and atmospheric conditions in the dialog above for any session and for any user-chosen time spans.