Signal head description

[Holshot14]

Hello, I live in chambersburg pa. This is an upgraded signal the NS recently put in. But there are only two lines and three heads. Could someone explain what the three heads mean and what the different colors would mean?
I have a higher res pic if someone needs it, but all three light are currently red
Thanks

 

[Pat]

Different combinations of colors indicate different things about the track and route ahead.

 

[Holshot14]

Thanks for the picture, I have ssen that before but there is only ever one light per head lit up. Also why are there three heads and only 2 tracks?

 

[Pat]

If they illuminated more than one light per head at a time there would be no point in having the three colors available. In the chart only one color per head is used at a time. Different combinations give the engineer different a instruction. A simple "proceed" at track speed, "approach" the next signal prepared to stop, that they will be taking the diverging route (the second track) and so on. Every indication might not be needed at this location but what they do use needs there heads. Follow the descriptions for each indication.