Now that the main loop of track is complete and running  I thought it would be fun to add more visual interest with a second train shunting automatically back and forth on the station and mine spurs as the first train racks up miles on the main loop. To accomplish this, I picked up a Circuitron AR-2 auto-reverse circuit at my local hobby shop.
|The AR-2 circuit board.|
The AR-2 comes complete with a pair of optical sensors that must be installed between the ties at either end of the train's run.
|One of the tiny optical sensors ready to be installed between the rails.|
|Optical sensors installed at both ends of the run.|
|Everything wired up, soldered and ready to test.|
I should mention that since this is basically just an automated polarity reversing system it is only useful with DC systems and will not work for DCC. Of course, I'm a big believer in having my cake and eating it too so I'll be wiring the layout for both traditional DC and Digital Command Control. When all the wiring is done I'll be able to flip a switch or two and choose between automation like this, DC cab control or full DCC. If I do it right, I'll even be able to operate some blocks on DCC and others on DC.
I tend to put off wiring projects as long as possible but this one only took about an hour to complete and now I have two trains running on Thunder Mesa! Thanks to Circuitron for creating a great product that has me excited about other automation and animation possibilites for the railroad. More to come!
Although the Circuitron AR-2 has performed flawlessly, I am no longer using it on the layout. As the railroad has grown, my focus has shifted from simple display to more realistic operation and I'm now using DCC to run trains almost exclusively. The AR-2 unit has been uninstalled from the layout, but I may bring it back in the future to automate trains on the upper level On18 Calico line.