I've been trying to find a solution for duel aspect signals and cant find much online about it. I didn't want to pay for a pre-made one and they seem a bit thin on the ground anyway so i decided to make my own.
I wanted a simple 2 aspect signal with red and green lights and a simple 3 core cable connection to the signal box.
I decided to use spray can lids for the light shades. I used a 50mm hole saw to drill out the top of the lid (be careful doing this - I used a pillar drill) and then cut them in half.
I managed to find an outdoor junction box that seemed suitable so I cut 2 x 50mm holes with a hole saw. This junction box is really handy as the whole unit can be opened with the snap shut catch for maintenance while still fixed to the pole. The box I found measures 17.5cm long x 11.5cm wide x 7.5cm deep. Ideally, I would use one a bit slimmer than 11.5cm but it does need the 7.5cm depth because of the GU10 connectors on the back of the lights.
Then I glued the caps over the holes. I also moved the cable inlet to the side of the box.
Obviously I needed to use rain proof IP64 cable glands to keep things safe as its 240v.
I got a red and a green 240v 50mm GU10 LED for just over £3 each and found a couple of glass covers from an outside light to insert them into. The reason for the old light covers was because there was a tiny gap between the bulb and the box and the hot glue around the bulb would have been visible. On reflection, I would have drilled a 40mm hole in the box, this would have done away with the need for the covers from the old light and I could have just glued the bulbs in directly.
I then glued the LEDs into the tube from the old light. Because of the very long life of the LEDs, I'm not going to bother making them easy to replace I'm just gluing them in with the glue gun.
The surround of the glass light cover was bigger than 50mm so I glued this to the inside of the box to make it waterproof. Ive tested the heat output from these lights over an hour and they didn't even get very warm to the touch so im not worried about overheating etc.
Then I sprayed it all black (before inserting the lights)! I'm going to operate the signal from a 1 gang 2 way light switch in the signal box, in the off position it activates the green light and in the on position it activates the red. See the diagrams I did below for wiring - very simple. The signal will operate with just a 3 core cable from the switch in the signal box.
See right wiring plan: Red is now ON as the switch is in the on position in the signal box.
The switch only affects ts the live wire, the blue wire is connected permanently.
For green to be activated, I just switch it the other way..
Considering its home made, I'm quite happy with the look. Ideally I will try to get some authentic looking lenses to go over the lights as there is no obvious light colour (the LEDs are clear to look at - you only see the colour when they are switched on.The LEDS are a little too bright but they are the lowest power ones I could find with the time I had.
I put the red at the bottom as I have read thats correct for full size railways - because of potential snow buildup on the bottom cap obscuring the top light?
I know I found some of the items around the workshop but you should be able to make this for about £25.