Mike wrote:
"From what I can see in the reference below, and the links on its page, I believe that semaphores are not covered in any of the existing tables; that they are set up only for lights. Am I correct?"
"Yes and No" (one of my _favorite_ answers!).
- Most JMRI signaling system definitions do not _specifically_ call out masts with "semaphore-style" heads. Exceptions include "B&O-1980", "B&O-Semaphore" and "BR-2003".
- JMRI signaling system definitions are _not required_ to define _every_ style of signal head that a given railroad actually used. Depending on which head styles the JMRI developer was willing to create, given signaling system may or may not include "semaphore-shaped" icons. Some pre-defined JMRI signaling systems have defined masts with a greater variety of "head" types than others.
- It is important to note that many prototype railroad rule books define their signaling rules in a very simplified way. The rule book I have most easily available states "The aspects may be shown by color of lights and by the position of semaphore arms." That rule book does _not_ specify which types of signal heads present a "color of light". So a given signal aspect might be conveyed by any signal head type: semaphore, searchlight, color-light, color-position-light, position-light, etc.
- From the perspective of the icons on a JMRI panel, most users find that it does not matter what the icon looks like, so long as it correctly represents the "aspect" of the associated signal mast and so long as it is properly interpretable on the finished panel. So a layout might physically implement a combination of semaphore and position-light signals, but the panel might only show "searchlight" icons. This can be thought of as a simple matter of practicality, ease panel development, and/or ease of interpretation by a panel viewer.
One key thing to understand is how to map control of a given model of a physical signal to something that JMRI can control. In many cases, this is done via proper configuration of a JMRI "Signal Head" object which controls a given head on the physical signal, and in other cases it is via proper configuration of a JMRI "Signal Mast" object. Which of these two defines the hardware interactions between JMRI and the physical signal depends on exactly what signaling hardware you are using, and can be very layout-specific. If interested in that topic, I suggest that you investigate the hardware you are using and how it is proprerly controlled via JMRI, and relate that to the JMRI "Signal Heads" and "Signal Masts" documentation. If you need further help on that topic, feel free to start a new thread...
Regards,
Billybob
