With Fall upon us, I can finally get back to my basement layout. Long story, but this is a re-build of a former layout in the same spot but with a bit more real estate and the incorporation of DCS for the first time for me (I connected a TIU to our Christmas layout in 2019 to learn more about DCS). Two questions as I forge ahead.
FIrst, my two concentric U-shaped loops will be roughly 75' - 100' of track, and I plan to use the "Star Wiring" method. What's a good rule of thumb for the length of each section running back to a terminal block? 25' gives me 3-4 segments, but 10' gives me 7-10 segments with a whole lot more wire consumption.
Second question, what's a good rule of thumb for power required to run TWO trains, say 8-10 cars long. As I recall from my old layout, a single postwar LW wasn't sufficient for two trains. Back-of-the-envelope math says 100-120W / 18V gives me 5-7 amps among two trains. Thinking that's barely enough for a non-lighted freight train let along a string of lighted passenger cars (haven't made the jump to LEDs yet). Thinking 3-5W along per passenger car.
Seems like my options are, as others have advised me before on prior posts, to invest in some 180W bricks from Lionel or breaking each of my loops into two separate power blocks and use four transformers (since I have a plethora of 90 - 120W transformers). The latter, of course, means the two loops consumes all four TIU channels.