This is a copy of the original Märklin 7188 signpost.
The original signpost is designed to hold miniature light bulbs and is switched by a relay
In a modern digital railway setup you don't need the relay any more, and you want to use LEDs.
So, I redesigned the signpost in Blender to hold LED's.
Furthermore, I replaced the wire gutter in the original by a small tube.
The bottom of the signpost is hollow to accommodate the resistor.

Ultimaker

Ultimaker Original

Yes

normal

20%

You need to print the signpost on its back. Support is absolutely necessary.
The separate fence is also printed on it's back, no support needed.
The clip also needs support

The signpost and the fence on the top are printed in separate prints.
For the signpost you need to clean the surface properly to get rid of the support remains.
The holes for the LEDs are pretty tight and accommodate 4mm LEDs with a flat top.
The wiring I used is Litze-wire with an outer diameter of .65 mm.
The base of the signpost is hollow so you can add the resistor if connected to a 16 volt transformer. I used a 1.5 K resistor.
The clip is only needed if you want to steady the signpost with the aid of the track (see the first picture). Normally you would fasten the signpost to the setup itself.

I used Blender to design the signpost.
The tube at the back of the signpost has a diameter of 1.5mm, just enough space for 3 wires of .65mm