What's that you say, signals on a small narrow gauge line ? Well, while to my knowledge no automated signalling was ever done on any American narrow gauge railroads, it certainly could have. Low labor costs back in the day would have made it less expensive to use manned posts to control trains than to invest in a signalling system but it's my railroad and I decided I wanted some minimal signalling. I have always been fascinated by semaphore signals and when I saw Indiana Signal Systems semaphore signals I was hooked.

The first application I had was for a signal to be located at the departure end of the yard to let the train crews know when they were clear to leave the yard and enter the mainline. This would be mostly for appearance but when and if operations are staged it would provide a method of spacing out locals as they leave the yard. The signal would remain in the green position until such time as a train left the yard. On it's way out it would trigger the signal to change to a red indication and hold for some period of time before transitioning back to green. The first semaphore I bought was set up to use photo sensors to detect the passing train and change position and hold for an amount of time determined by some DIP switches mounted in the control box portion of the signal.  I was dubious about how well this would work based on my experience with these types of sensors used on industrial machinery. Even in an indoor application various reflections and lighting conditions can cause problems and I felt it would be even worse outside with the effects of the sun. Turns out I was correct in my assumptions as I had little luck getting the signal to work with any degree of reliability. After conversing with the manufacturer it was determined that the signal had an issue and was returned for repair. When I got it back it did work better but I still wasn't happy with it and after further conversation with manufacturer I was provided with the information needed to modify the circuit so I could trigger the signal using a track side switch. Locomotives would have magnets installed to activate a reed switch located between the ties and trigger the signal.  This was implemented and worked quite well and the magnets would be needed for other functions later on.

The signals themselves are not weather proof so they could not be left out all the time. A method would be needed to allow them to put away when not in use. I ended up using weather proof plastic electrical boxes to protect the electrical wiring and connectors and mounted the signals to the lid of the box. When not being used the screws holding the lid on are removed and a blank lid is installed in its place. The box is sunk into the ground up to the lid. The multi conductor cable which brings power in and connects to the under track switch enters through holes drilled in the side of the box which are sized for a snug fit and sealed with silicon caulk.

The photo below shows the first signal purchased mounted to an electrical box. The two holes in the side of the control base were for the photo sensors and the one on the front was for access to the on-off switch. As it came from the manufacturer it could be powered by a battery or external power.

The next photo shows the box set into the ground with its not in use cover installed.

The next photo shows the signal installed and ready for operation.

The other application I had for signals was to protect the Gully track work. The Gully section with its 'S' curve leaves an engineer basically blind to trains approaching from the opposite direction. The plan was to install a signal at each end that would provide a stop indication to the opposite end when train entered the other end. Since there is not track power the signals only provide information and do not control them. They would come into play only during operations to control entry to the Gully and engineers would be required to abide by the signal indications or suffer the consequences. When I purchased additional signals I found out upon receiving them that the design had changed, both physically and electrically. Apparently the original electrical design impinged on someones patent and needed to be changed. To my mind this was better as they now could be triggered the way I had modified the original one. The next photo shows the newer design. The connections at the bottom provide options for cascade them and other things.

To make this all work required a bit of additional circuitry. For one thing I needed a time delay longer than what is provided with stock signal as I needed to hold it's indication long enough for the train to transit the Gully. For this I used a commercial delay on release solid state relay. These were mounted for convenience sake in the waterproof junction box located under the power house at the engine facility. Once the signals were located all the interconnecting wiring was buried and connected. In operation when a train enters the Gully from the upper end it not only triggers the signal at that end but also activates the relay that energizes the lower signal and holds it in the stop position for a period of time long enough for the downhill train to clear the Gully. The upper signal only holds the stop position as long as is set in its internal circuit before returning to green. Once the time delay relay times out the signal returns to the proceed position. The function works the same way for trains entering from the lower end of the Gully. So as long as the engineers obey the signals all will be safe. The next photo shows the two delay relays mounted in the junction box below the power house. Low voltage DC and air for use on the layout enter from the garage on the left side through the large conduit and is distributed where needed on the layout. The two relays U and L for upper and lower are adjustable from a few seconds to a couple minutes with the adjustments on the top. These are set to provide about 90 seconds which is more than enough time for even a slow moving train to transit the Gully. 

The next photo show the signal at the upper end of the Gully. The section house houses the electronics that controls the loop switch and the signal location stops the train just short of the sensor that triggers the loop switch. This will be discussed in the article on loop switch control.

In the next photo a train has just passed the upper signal. I had stopped the train to take the photo and while composing the shot the signal had timed out and was cycling back to the clear position. It makes a brief pause in the yellow position and that's where the photo caught it.

All pretty simple stuff and more for looks than function but that's part of the fun of trains ! If you have any questions please feel to email me.

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Updated   4/5/19