I used the Circuitron BD-2 circuit boards. Circuitron electronic boards allowed me to install a system free of the layout's electrical track circuits. One Circuitron board was required for each block plus the trackside signals. There is a cost to install trackside signals no matter which electronic system you pick.
If you don't have the funds to do the entire layout, you can start with just one track block. Pick the area of the layout where you are most likely to get the most attention. After you have installed the system as your friends bestow positive comments upon you. start to plan for the next block.
Now back to my newly install home interlocking block signal. The east bound home interlocking signals on my layout can display 4 different combination of aspects.
Green over Green = PROCEED at allowed speed per employee rule book..
Red over Red = ABSOLUTE STOP Only instructions from the dispatcher can over ride the signal.
Green over Red = STOP The track ahead is clear, however the turnout at the junction is set for the diverging route. An east bound train may be leaving Westchester Station. After waiting for 5 minutes contact the junction tower to see what is going on.
Red over Green = STOP The track ahead may be occupied and the turnout at the junction is set for your route. After waiting for 5 minutes proceed at restricted speed prepared to stop within your view of the track ahead.
My review of the trackside signals on my layout gave me more realistic signals. I hope visitors to my layout will enjoy watching the signals change color more than they have in the past. Now if I can only get the road crossing signals working! There are 3 of them. Maybe next summer when more work will be done on the layout the grade crossings can be made to work. The balance of the year is for model building and re-working older models.