"We have already added the Bridge rectifier, the correct capacitor, and the resistor. You just connect to your track power!"
"You will notice both leads on these LEDs are black. That is because the polarity does not matter. The bridge rectifier takes care of this. Connect "either way" you are covered."
Stan, I took the above directly from the modeltrainsoftware.com website where I get the LED's
Thought it might help with the wiring issues.
Frank