Now that I removed the previous LED strip, I can focus on the ESU strip. I start with the intermediary car; it's the easiest since there is no cabin or decoder. A full ESU strip and a shorter one with 6 LEDs would work well for both levels:
I follow one of my previous post to connect the "full" strip with the shorter one:
And it works nicely!
Time to install those into the car:
Everything looks great for the lower level, but on the upper level, the lighting strip in the middle section actually stands too low as it is at the seat level. 😓
I'd need to cut the "full" strip into three sections so that it follows each level of the ceiling. More wiring ....