Train Cat Models (now no longer available). It was assembled with CA, then some parts were re-done with solder. Some old lumpy steel colored paint gave it a rather poor finish. It was then modified to enable the installation of four extremely tiny LEDs.
There are eight wires hand-threaded through the main vertical tube. The Styrene parts below the signal are to enable it to be easily inserted and removed from the layout. An Arduino with a short test program is being used to cycle all of the LEDs to test them.