New railway signals do not use special colors - they get dark in night view. Neither color light, neither led, neither mechanical signals. I'm not sure - it may apply to standard pakset as well.
May I ask to which specific signals you are referring?
All sorts of railway signals. Color light (also square and, LED versions). Mechanic signals should have small lights too.
For the reasons given in the other thread, fixing night mode specific issues is a very low priority, as pak128.Britain is not designed to work in night mode.