Monochromatic ????????? colors with the same hue but different values (brown and taupe)
Analogous ????????? colors that are next to each other on the wheel and thus similar (green and yellow)
Complementary ????????? color-wheel opposites that give the most contrast and are exciting to the eye (orange and blue)
Works for interior design works for coaster colors. Just some ideas.
Edit:
Well you might as well name it and theme it to jokers revenge with those colors.
Actually, changing the color of the train wouldnt make it so bad. Maybe with a grey car. And seat color less neon.