Realistic Control for Grade Crossing Flashers
A complete description of an electronic circuit you can build to drive grade-crossing LEDs, triggered by a block occupancy detector.
Three-Aspect Signal Driver
This article shows the design diagram and printed circuit board for making Automatic Block Signaling and Absolute-Permissive Block Signaling. Includes parts list and installation diagrams. Shows wiring for three- and two-aspect color light signal wiring, PRR and B&O position light signal wiring.