>Because good binoculars reach so far, you can sometimes see past the first signal. There was an engineer who ran a red block and crashed. He was on a yellow following another train so he went to the binoculars. It was a short block and the train ahead was just a few cars.

>He saw a clear signal, throttled up, and crashed into the train ahead. OOPS! The clear signal was for the train ahead. This guy never noticed the red signal for his own train, too busy looking thru binoculars.

This is why binoculars are no longer permitted.

The lightbulb and doublet fresnel lens combination, like the ones in the pic, works just fine, provided all three colors are aimed in precisely the same direction, and that direction has to be for the oncoming train. It's no different with seachlight signals. The problem is that the rrs and their signal departments have gotten rather careless in quality control (the manufacturers have too).