The information is out there--I think this may be one of the Maxwell drawings that were copied off actual D&RGW prints. All the standard heralds and most of the lettering had a master print, and in the case of the D&RGW, sized for different uses from bridges to locomotives:
[
www.flickr.com]
and originals survive as well, like the Safety First sign in my collection:
[
www.flickr.com]