well Ben. To answer your question, almost all of the time with a spring switch junction, it only directs traffic up one route therefore not needing a signal that can show diverging clear or medium clear or what have you. with this being said imagine that because there is a spring switch forcing the traffic up only one track when facing the points that its just a single main line. thats why you have only one signal head and in this case it just happened to be a tri light instead of typical searchlight signals found on the FEC