The powerplant building is a huge building on the layout, with a couple of high chimneys.
Because of the height, the building and the chimneys have red warning lights installed, and some flashing beacons, warning airplanes about the high chimneys.
All the lights are installed using fibers for the lights and WS2811 adresseable LED's controlled by an Arduino microcontroller.
To easy connect the fibers to the LED, I have 3D-printed a holder for 4 LED's, with several holes for the fibers.
The actual 8 mm WS2811 LED's from Aliexpress.com. Also available in 5 mm versions.
Video showing the finished flashlights: