Note for modders: Sol introduces 'fog' which can obscure or 'darken' distant objects, small tracks are unaffected (<3km), but for DEM backgrounds etc there is a parameter to adjust (ta_fog_distance) in sol__track_adaption.lua (Sol's defaults at the time of writing bring in fog at only 2 or 3 km). FWIW I set ta_fog_distance to 3.33
