Wonderful idea. I love how you got power up to the shell using the brass tabs. I have installed LEDs into some of my older shells and the disconnect is a pain when I remove the shell. May I steal your ideas please?
I actually built my DCC command module using a clone Arduino Uno Rev 3 board, a clone Arduino Motor Shield, and Raspberry Pi 4. I bought the hardware off Amazon and Adafruit, software was off Aduino, Raspberry, and JMRI (Controller software). There are a few videos you can use for this.
I saw this thing on YouTube and thought "Why not?" It works well. I am able to program my locomotives, etc. I have not added control to my switches yet.
The whole thing cost me a total of about $100....and I get to use the Raspberry Pi for other things as well