Install a blinking LED in place of the existing MARS light.
Thanks, everyone, for your help. I will order a MARS LED board from Dallee Electronics and install it myself. Thanks, Lionel, for an expensive lesson.
I don't understand your frustration. Nowhere in Lionel's product literature for that set does it say it has a MARS light. This is all it says: "Directional lighting, including LED headlights".
Ron