We have embarked on developing an O scale signal line. A few years ago, I was asked to provide some C&O Cantilever signals for a large O scale layout outside of Detroit. Use Solidworks  3D design tool, I came up with the Type D 3 color vertical signal head that the C&O used on their mainline cantilever signals. This is a photo of one of the signals installed on the layout. Below are some of the current parts available.

Gribbell C&O 1

BO005 Brass 3 Color Vertical Type D $6.00 ea.

BO005 Brass O Scale 3 Color Vertical