So, for several reasons, I won’t simply upscaling the textures from the other mod and using them.
When it comes to maintenance, I want to be independent of another source that might change.
The textures from the other mod have artifacts and jagged edges that would make upscaling very difficult—and you can’t create clean upscales from messy sources.
If you’re mainly interested in the color of the railings, I can try to see if I can come up with something similar.
I've only colored the top part of the railing so far. If I color the bottom part, the transition to the pylons and ramps looks really out of place, but maybe I'll find a solution.
I reduced the brightness and increased the red component.
I've also colored all the elements that are part of the railing. I would leave the red crossbeams between the tracks their current red color. That way, the transition to the pylons and ramps will look better.