I purchased BLMA #4038 3 light block signal. There are 4 wires (common anode &1 for each LED). There is no color coding on the wires so I can't tell which wire is the common & which go to the different LED colors. I'm hooking this up to the Log Rail SA-1 signal animator. 3 of the wires have copper coloring outside and 1 has a reddish coloring.
The red should be the common,and the others were tagged with their respective color on the BLMA signals I have. If the tags are missing,you should be able to hook them up to the SA-1 and just move them around until they light in the correct sequence.
Mike