by ExCon90
In the quick succession of clips at the beginning of a Retired Railfan video there is a shot of an LIRR diesel passing a color-light signal displaying green over green, which drops to red over red as the head end passes it; it's on single track, non-electrified, and the signal has a small yellow sign on the mast displaying a black C over O. The only time I've seen G/G was on the NYC before MN eliminated automatic wayside signals; is G/G something new on the LIRR, and how does it differ from G/R?