bullet and decided to use a computer for the dispatcher to control the signals. Af- ter quite a bit of trepidation and a steep learning curve I am very glad I did. The hardware system the dispatcher uses to control each semaphore is shown in the schematic diagram on page 62. The Dig- itrax’s Loconet bus sends bidirectional control information to devices scattered about the layout. One DS64 switch con- troller attached to Loconet is used for each train order station. The DS64 can control up to four turnouts and receives up to eight binary inputs which allows each train order signal (east and west) to be set just as you would address a turnout, it accommodates the Acknowl- edge-East and Acknowledge-West push- button inputs and can finally turn on the fascia-mounted Acknowledge LED’s to provide feedback to the crews that their acknowledge signals were received by the system. One wrinkle was the DS64 could not directly switch the ¼ amp required by the Nitinol semaphore actuators, but it could drive latching so- lenoids for this purpose. The relays in turn switch the power to the Nitinol and the fascia-mounted indicator LED’s. I interfaced the computer to the Lo- conet with a Digitrax PR3 and dove into the fascinating world of JMRI (Java Model Railroad Interface–an open source program for model rail- roaders that can be found at: http://
jmri.sourceforge.net/) and Panelpro! This is where the learning curve got very steep but the Yahoo®
JMRI forum,
Eddy Aycock follows his train through South Slocan passing the pigeon hole board from the operator side (page 60). Hanging around his neck is a lanyard attached to a clipboard containing the paperwork for the job he is working. A copy of the timetable can be found on the back of the clipboard. This 2¹⁄₂″ tall, unlit model was the test proto- type of the Nitinol wire-driven train order semaphore (top left). The final semaphores use nano-LED’s to light their aspects. When a ¼ amp passes through the Nitinol wire, it contracts rotating a pulley 90 degrees and dropping the board (top right). Springs be- low the main mast return the boards to their upright position when the current is turned off. This scene (above) features a finished train order semaphore at Farron summit.
epoxied to the semaphore base allow the signals to be installed from above into DIP sockets glued to the layout, which allows the signals to be easily disconnected from the supply and con- trol wiring and removed when needed. As a supplement to these small sig-
nals, I also mounted train order indica- tor panels to the fascia with bright LED’s showing the crews what the sta-
RAILROAD MODEL CRAFTSMAN
tus of the westbound and eastbound signals are at each train order station. For feedback, the indicator panel also includes a pushbutton and white indi- cator LED so that the crews can ac- knowledge to the dispatcher they have received their orders.
After toying with the idea of a dedicat- ed switch box for the dispatcher to con- trol each of the semaphores, I bit the
and especially a series of PowerPoint® presentations on Panelpro, were very helpful. It took me about a month to design the dispatcher panel in Panel- pro but the power and flexibility of this program really shines now that I have it. By clicking on one of the CTC-like switches with the computer’s mouse, and then the corresponding “code” but- ton below it, the dispatcher panel comes to life. Relay sounds “click” and “clunk,” semaphore schematics change and logic locks the signal from being cleared without an acknowledge indi- cation from the crew. Out on the layout the semaphore aspect and position changes and the panel-mounted LED’s also confirm that there are orders at that station. When the crews have re- trieved their orders from the pigeon hole box, read and understood them, they press the acknowledge button on the train order station panel which rings a bell on the dispatcher’s comput- er, audible in the layout room, and flashes a light on the dispatcher’s pan- el as a gentle reminder to clear the sig- nal. The dispatcher can also control the fast clock and its rate from this panel. Finally, we have toyed with tying in the Panelpro logic system to automati-
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