I have some passenger cars that I would like to do interiors on and light up. My main issue with this feat is figuring out what to do about the lights. Do I need a dcc decoder in the cars to illuminate them? If so would it be wise to add connectors and wire all the cars to one decoder or do I need to install a decoder in each? I attempted to try an led on the rails to see if it would work but it wouldn’t light up. I touched it to a dc power pack and it did. I’m guessing that led lights won’t activate unless there is dc due to it being an alternating current and current only flows one way through an led light?