Done! I finished the layout and the box and I am really happy with it. The biggest change is that I realized I can't run both trains, the switch, the lights and a single board LCD screen on a 9v battery. Duh. The lights on the cars didn't have enough current to light. Also, when I turned on the lights the max train speed would drop in half. The switch wouldn't work reliably either as the 9v discharged. I tried using a 3s 650mah lipo and that worked. Except the current drain was pretty high and I took it down to critical voltage really fast. Not wanting to have to install a low voltage cutoff, deal with recharging a RC car lipo or set the whole layout on fire, I went with a 12v power bank.
Naturally, switching from the 9v battery to 12v power bank created another problem. The lights on the cars worked but now the LCD screen wan't working. I was using the 3v output of an Adafruit ItsyBitsy with the 9v input to power the LilyGo TTGO screen. The 12v was too much power for the ItsyBitsy and it wasn't working. It was designed for a 5v input. Yeah, I was pushing it with the 9v but it was working. Ideally, I needed to get the 12v down to 3v but I couldn't find anything readily available and small enough to work. The train board sits about a quarter inch above the box so there is not a lot of space. I settled on a weird bank shot of using a RC BEC to get down to 5v and using that to power the ItsyBitsy which would then send 3v to the LilyGo. Got it? It actually worked.
The 12v power bank is a 3000mah model which gives me plenty of battery life. Shockingly, its bigger than a 9v battery, so I had redesign the control box. This was a good thing because the original control box didn't fill up the space I had cut out for the controls and I had a piece of black acrylic cut to fill the gap. With the new box I got rid of that problem.
So now with the new battery and control box everything is working! All the lights come on and the trains run at full speed even with the lights on. The switch is very reliable now as well.
I'm planning on building a smaller layout in a hidden storage book I bought using the leftover track I have. I'm just going to run a single car on the track so I bought one of the little Japanese metro cars. I have to admit I really love this little guy and it looks great running on the bigger layout with one of the Shinkansen trains. I may have to get another. This is addicting.
I also took this layout to the Downtown Columbia Mini Maker Faire where CCHobbyFun had its first booth. I had the RC Knight Rider car, Daft Punk helmet and the train layout as active displays. The train layout was a huge hit and an absolute kid magnet. As my wife explained it to me, "You built a small train layout at child height. What did you expect to happen?" True.
I'll end this with a video overview and footage of the trains running.