I love you Chris. :-*
Is it still a Mars light? Used to be that whole assembly rotated, so it could sit at any angle when it stopped moving... but I can't imagine the mechanism is still there, let alone functional.
They got to be a maintanance headache, so instead of the revolving figure-8 pattern, the Metra engines just have a light that sweeps back and forth now. Couple old timer engineers complain that it puts them to sleep. The Mars pattern was less inducive to hypnotizing you because it was less predictable.