One thing I've found to be really helpful in applying new settings to a session using the environmental controls is to choose a scene that includes most of the elements that you wish to impact.
Then experiment with it until it looks real:
That is: Select a camera viewpoint that includes both near and far distant scenery and including a body of water; PBR procedural track and close-up, detailed locomotive(s) and trailing consist; Nearby 3D vegetation and PBR grasses/ clutter; Distant fields, forests and hills/ mountains.
Other trackside objects at intermediate distances, such as relay boxes, signals, yard buildings, etc. all contribute to the 'actors in the scene' that you wish to spotlight and assess for lighting effects.
Pay particular attention to shadows to avoid dramatic contrast in light and darkness. In real life, most shadows are quite subtle and show good detail in shaded areas.
Look in particular at the bogies on the locomotive, and in the shadows beneath any nearby trees to ensure that they are not blacked out but rather show well-defined detail of their components/ undergrowth and leaf litter base.
Whether or not HDR or High Dynamic Range is available on your output device/ monitor(s), focus on achieving good tonal balance and broad spectrum gradation of both colour hues and shades of grey between deep black and bright white. (Pays to start off with a properly calibrated monitor).
Since you will be primarily assessing a static scene whilst you manipulate these controls, you can afford to increase the performance setting controls towards their maximum or Ultra values during this 'atmospheric conditioning' process.
The exceptions to the maxed settings that I'd suggest is for the Post Processing controls. To avoid the preset visual distortions of the Ultra and High PP settings, set this to Low, or better still, adjust the values using the Manual settings available in the Launcher, Developer menu.
When complete, you can revert to your preferred settings for dynamic gameplay/ moving objects, etc. whilst retaining the benefits of the optimal tuning achieved using the maxed out settings.
This allows you to perfect the shadows settings, in particular.
One rather counterintuitive discovery that many of us have made that is quite different from the T:ANE environment editing suite setup, is to deliberately set the Sun Color Preview pane to a uniform, dark-ish grey using the RGB control dials, whilst having higher, (whiter) RGB values for the Ambient Color Preview pane. This will give your richer colors, more realistic ambient lighting and more detailed shadows.
Do all of this with multiple control-point 'dots' applied to different times on the clock and preferably with the fog set to OFF between the hours of 9am and 5pm during this lighting adjustment phase.
Try to avoid the extremes (i.e. all the way up or down) on the new and much-welcomed brightness slider to the right of the familiar preview panes - even at midday.
Finally, regarding water, assess this by looking at a body of water in your scene after ensuring that the performance setting is set to 'Ultra'.
I personally find setting these initially to a uniform very dark grey (all RGB dials wound right back) looks more realistic than almost any other setting for deeper water. You can then add a tad of blue, green, aqua or brown to taste to fit your scenario location, but you'll find that even with the minimised RGB settings, water bodies will faithfully reflect the sky colours and clouds very nicely. Shallow water colours are best influenced by the texture applied beneath in any event... Water settings are best assessed using either the 'Calm', 'Glassy' or 'Slow Rippled' initial presets.
It helps to be an experienced photographer or landscape painter in assessing the lighting environment at different times of day and season, since many of the colour & lighting theory principles can be applied to your Trainz environment.
But these same principles can still be 'discovered', learned and applied by novices after investing a suitable amount of time to experimentation and methodical testing of the lighting controls and a scene of your own making in TRS 2019.
Getting it right can be soooo rewarding!
