But as a completely separate question, what was MTH thinking calling their CC-0000015 a 6V light?
I see your comment about fixing subway cars that apparently had this incestuous relationship between red and green LEDs.
OTOH I can see where there might be applications where one would want to plug in an LED based 6V light into the molex connector of a PS2 or PS3/2 LAMP output (headlight, tail-light, interior light, etc.) that is meant for a 6V incandescent bulb(s). This would give you DCS on/off command-control of the 2 red and 2 green LEDs.
Well, if nothing else, maybe all these buzzwords (let me throw in a couple more below) will get caught by a future "search" on this topic!
Two series connected red ceramic stem LEDs on molex harness: CC-0000062