I probably should not do this, but I have the "Supersonic High Speed Train Mod" installed, and I tried to use these Trains to fly over the Train Ramp...
My Game crashed, and this is the Error:

Error while running event RenaiTransportation::on_nth_tick(1)
Invalid color value. Values must be >= 0 and <= 255. in property tree at ROOT
stack traceback:
[C]: in function 'set_color'
RenaiTransportation/script/trains/animation.lua:78: in function 'updateScale'
RenaiTransportation/script/trains/animation.lua:25: in function 'updateRendering'
RenaiTransportation/script/trains/on_tick.lua:453: in function 'handle_trains'
RenaiTransportation/script/event/on_tick.lua:6: in function <RenaiTransportation/script/event/on_tick.lua:4>

Maybe that high speed train doesn't use custom colors, I'll have to see what properties that train has

Okay so a while back I had someone help me update my mod when 1.1 came out and part of it was helping me update the animation code to be a bit smoother and add shadows. Part of their changes was to adjust the fading of the shadow with the jump height but apparently with the SUPERSONIC trains it can jump so high that the value used to calculate the shadow fading can wrap all the way out of bounds for what factorio recognizes as colors. So I adjusted the formula a bit so that no matter how high the train goes it'll still be within the accepted range and all should be good. Also it fixes that after a certain height the shadow starts to get darker again. Now the shadow should fade as you expect. Check out the update in 0.8.9