Summary

Simplistic version of a signal head scaled approximately to oo scale.
Printed on a Elegoo Saturn 4 Ultra. The post is a 3mm styrene tube. LEDs still to order but SMD. I may try to file down a 3mm LED and there should just be enough room. There is 3.5mm for the LED,but the holes are 2mm for a SMD to shine through and a future transparent cap to be printed, or even a blob of transparent glue.

This object was made in Tinkercad. Edit it online https://www.tinkercad.com/things/9eWRbIOQa8l