I know that this post is almost a year late, but here goes!!!!!!:
Here is the NYC info. I was referring to regarding NYC's Pacemaker Service from the late 1930's until WWII, when it wads stopped.
The original Pacemaker cars were Green, as is noted at the bottom of the post.
And! Today, I met a fellow who said that the First start of NYC's Pacemaker Service that the box cars were green with the Pacemaker Service script, just below the roofline and to the left of the door, in white lettering and below that was the NYC logo, also to the left of the door. When, WWII broke out the Pacemaker Service was discontinued, until after the war, about 1945/6 and with the more famous Red and Gray color scheme.
As, of this time, I still cannot find any other info. or even B&W photos. of the late 1930's, to WWII, Green Pacemaker Service box cars.
As such:
http://www.ominousweather.com/NYCLines.html#Pacemaker
Ralph