This small circuit board is a power buffer for a model train coach lights, to provide flicker free lights. This elliminates the internal lights to flicker when the trains goes through dirty section of the track.

The big capacitor stores charge and provides power for the lights when the power pickup is not happening. The small DC-DC buck converter is used to reduce the track voltage to for the lights. In my case I used 9V to power sections of 12V LED strip which results in a more prototypical illumination.

Components used:

• 2 pin female pin header, or any compatible 0.1 inch pitch header, socket
• Bridge rectified in DIP package
• 22000 uF, 25V, Jamicon capacitor
• DC-DC buck converter: https://www.aliexpress.com/item/1005005084434791.html
• 10 ohm, 1W axial resistor

If you want to see the whole build, design considerations, check out this video: https://youtu.be/SKURT_F4RbA