I too grew up next to the NY&LB, although it was the North Jersey Coast by then. I believe there was a three-over-three near where the Matawan Creek Trestle stood. The trestle was way before my time, but the photo appears to show a staggered head three-over-three. There were also signals like that on the main, I think one is still standing outside Allentown, though long abandoned.
From the way you describe the sounds, I'm guessing the control relays were inside the signal itself, rather than in a separate cabinet.
I play with the real things now, though in the Metro St. Louis area, and out here it's all divergent route rather than speed signals.
Moveable bridges atually used a 3-over-3-over-3 combination, and the heads were in a vertical line, not staggered as on the block signals. Interlocking signals also had the heads in a vertical line, and some of those had three heads, others had two, depending on the speed of the crossovers.
