How far to stop behind railroad?

15 feet and make sure the light is green before you go

You must stop before your car reaches the line marked on the road. If your front bumper is above the line when you stop then you technically did not stop and can be ticketed. On the other hand if you...

Well you are required to stop 3 feet minimum of the tracks but im sure if the tracks are operational there will be gates that come up and down they are usually about 10 feet away

At the white stop line, or with no white line, at least 15 feet back.

You should be back where signs tells you to stop. If no sign, stay back ten feet from track.