I've had a few comments on my using battery power for the lighting in my passenger cars so I will explain why I went to a battery operation. I run dual mode on my layout, either the old standard DC for the majority of my locomotives or DCC with sound for my articulated steam locomotives.
I try to keep everything on the budget side as I'm retired and not rolling in money. I have wired almost every one of my 75 plus locomotives for DCC operation but I only have six sound decoders and six non sound decoders. Four of the non sound decoders have multiple function outputs for operating specialty locomotives, snow blower, camera equipped engines and my passenger car lighting.
I have two standard non sound decoders both in diesels, one is in an Athearn SD9 yard engine. The second standard decoder is in an Athearn SD40-2 chassis with a Cary E7A body and the lead engine for my Daylight Passenger cars when operating in DCC mode. The E7A's mate has a multiple function non sound decoder and it is in a powered E7B, also an Athearn SD40-2 chassis with a Cary E7B body.
I run the two E7 diesels in a consist pulling my Daylight passenger cars. The #3 & #4 function outputs from the E7B unit are coupled to a second E7B dummy with a Lithium battery and charger, the functions control a latching relay to turn on and off the passenger car lights. I often park my passenger cars next to my passenger station and turn off the power to that block, the lighting can remain on for extended lengths of time running off the Lithium battery.
I can also pull my non flickering Daylight passenger cars with a pair of DC Athearn SD40-2 chassis with Cary A&B E7 bodies and the battery E7B still powers the car lighting with the power off to the locomotives.
I paralleled the relay contacts in the E7B dummy with a magnetic latching reed switch attached to the center of the E7B shell to turn on and off the lights in my passenger cars when running in DC mode.