For the most part all I have ever seen is white marker lights but last month I saw 346 at CRRM with green marker's and 315 during Railfest last year had what looked like blue or green lenses in the lights but they were facing the rear so the white was facing forward...
Just wondering what the other colors mean, main reason I am asking is because yesterday I painted one of my model trains markers green because I liked how it looked and when I was looking it after I finished it hit me that I had no idea what diffrent colored lights even means