You have to understand the impact of dynamic lighting on OHW, points and fences to get a better idea of the settings needed to minimise the effects shown in the OP's screenshot above.
If you use Dynamic Lighting then you need to use the SSAA settings in TS2016 (2 x 2 is the "sweetspot") plus 8x AF and other sliders to suit [lowering the shadows reduces shimmer on a lot of occasions). Unfortunately you also need a decent monitor and a video card with enough VRAM to drive that monitor's resolution.
This gives the most realistic effect in TS2016 wrt time of day, weather etc.
Turning off DL means that you can use MSAA (Highest settings is best- shadows an water quality turn low as other settings don't change much) plus 8 x AF.
The OHW show less shimmer in many routes but this is a more "cartoon" like rendition of the sim, it can look a little too real and doesn't display dusk and night as well as with DL on. The monitor and the card are still relevant but less so than above. The present card should be able to handle this.
Limiting the fps via steam to say 30 can also help in shimmering.
If you use NVidia Inspector the shimmering can be reduced by a using negative LOD Bias - Allow and us a positive setting up to 3 (note this will also make the distance blurry).
The shimmering depends very much on the route with some being much better than others:
This is a shot from Liverpool to Manchester which does exhibit a lot of shimmer:
This is as good as I can get in reducing shimmer on that particular route.
pH