Serge NOELThese icons were extracted from images on Carsten S. Lundsten's web site.
Please see http://www.lundsten.dk/us_signaling/abs_st_sp/index.html#example
Directories are:
track-segments: A set of icons for drawing track segments. These
have a medium-gray background
searchlights: Seachlight signals for a track diagram.
aspects: displays of various signal aspects, organized by analogy
to the aspect signaling definition directories