Pennsylvania Railroad Position Signal
by Charles R. Hentz
During one busy open house, we had difficulty clearing a train that was causing a short circuit. Our Digitrax power management automatically tries to restore power when the short is cleared. We had eight small LED indication lights for our operators, but they are not visible from the layout. We needed a large light for each of our three main lines that would be more visible from the layout during crowded sessions. We decided to make a large Pennsylvania Railroad Signal which does have three amber lights to show the condition of the track ahead. This would be a perfect solution. To the visitor the signal looks like a nice piece of railroad memorably. But if the upper light is out, we know there is a short on mainline one. If the center lamp is out, then mainline two is short and of course the third or bottom lamp would mean mainline three had a short. A rotary switch allows us to show all three aspects of the signal with even a fourth position for off.
We found amber truck clearance lights that were round and two inches wide on the internet that looked great. For the hood on each lamp we could have used PVC pipe which happens to have exactly two inch inside diameter. However, the walls are fairly thick. Regular aluminum soda can rims have exactly the diameter to fit each lamp snugly. We used a can opener to remove the top and cut these with a band saw with a 45 degree angle using clamps to hold them steady. The 3/8 inch plywood back is 22 inches in diameter and the holes are 2 1/8 inch wide for the soda cans that are glued into the holes.