Thanks for the response! I think I am going to plan on using current sensors then and wire my freight stock with resistors.
The blue tube lighting is near the extreme end of the visible light spectrum and will be too dim to activate photocells.
I always use infrared LEDs and phototransistors aimed across the track instead of relying on photocells and room light.
I am planning on using blue tube lighting to simulate moonlight for night runs. I am also in the process of planning signals and crossings which brings me to the question: Do photocell sensors work under blue tube lighting? Or am I going to have to use current sensors for the signals and crossings to work properly under blue light? Thanks