These products provide signal animation for the purpose of appearing to operate meaningfully. When a loco covers the photocell, it turns the signal red. After a 10 or 30 second (selectable) delay the signal turns yellow, then after another delay, green. If all you want is for your signals to turn red, yellow, and green as your train passes and then leaves the area, these controllers may be what you need. But if your goal is to make your signals truly meaningful, you need prototypical signaling products listed elsewhere on this site.