signal mast color

[NW Mailing List]

Looking at photographs, it looks like during the steam era, signal masts were mainly painted black.  By the 1970's, most signal masts appear to be silver.  Does anyone know when the transition from black to silver signal masts took place?  More specifically, would color position light signals, installed beginning around 1959, ever have black masts, or were they silver from the beginning?

Marty Flick