I looking to add 6-8 block signals on my layout. I don't want them to control the movement of trains only to change as a train passes from green to red then yellow then back to green over a short period of time. Any suggestions?
Check with Dr. Dave Vollmer. At one time he used a signal controller that does what you want. Al PS Look here: http://logicrailtech.com/ at the Signal Animator.
Kato and Tomix signals do that for DC layouts using code 80 track. Just insert the section containing the signal and add power. The Tomix one will even turn red when you reverse the track polarity.
The Atlas G type signals with their detection and control boards are basically plug and play. I tried to use them on my T-Trak modules that I take to shows and found them to be not bright enough to be seen in the lighting of rooms that the shows are held in. I now use NJ International signals with relay circuits of my own design and they can be seen very well in any light. Current detectors are the best to use for train detection and I use NCE BD 20 detectors for this. The Atlas current detectors will not work with DCC though. The Atlas signal LEDS are wired common Cathode but the NJ International signals are wires common Anode, so you have to be careful while wiring as the NJ signal heads wont work with the Atlas control boards. The control for my signals uses cheap DIP relays mounted in IC sockets on PC boards. It comes out to be somewhat cheaper than the commercial control boards. Adds quite a bit of interest for viewers at the shows.
You can read about how I did it on the Sub in my thread (see signature). Model Railroader will have an article I wrote on how to do it in a future issue (sorry, don't know when). There are alternatives to the way I did it, of course, but the way I did it worked for me...YMMV!
