I use...

I use 3mm bi-color LED's for turnout indicators on my panels. Since I use Atlas switches, I also use their relay (#200) and can have signals on the panel and signals at the turnouts so operators know how to proceed.  

I made my own for dwarf

I made my own for dwarf signals in N scale, using surface mount LEDs stacked, and oppositely biased, with a single resistor and fed by a small AC wall wart. This has the advantage of only needing 2 wires per 2 LED stack. My turnout control was a DPDT slide switch - one side controlled frog polarity, the other the LEDs (2-3 sets per turnout depending on application, signalling each leg)

I bought some

Minimum order was quantity of 10 ($0.10 each). I bought them to fiddle with to see if I could use them on my layout. They work and appear to be capable of disassembly, but I have not tried that yet. Each LED is electrically separate. The dimensions are not good for N scale as a part of scenery, but could possibly be used on a control panel.

All Electronics does have many bargains on electronics and I have bought a number of items from them. Shipping on orders $75 and over is free, under $75 is a flat $8.00 shipping fee. I like ordering from them because they are not far away (Van Nuys, California), they process the order quickly,  and I usually receive orders overnight or within 2 days. They have a downloadable catalog in PDF format, all items can be searched online and each order is shipped with a printed catalog, unless you leave a note on your order to not include it. Many items have data sheets that can be downloaded as a PDF.

Here is the posting on their site for the stacked LEDs:

https://www.allelectronics.com/item/led-177/green/green/yellow-3-led-stack/1.html

The stack is designed to be printed circuit mounted, but could be used in a different manner.

Cheap LEDs, LEGO and coffee stirrers

I made some out of the cheap LEDs IIRC from All Electronics years ago. Back when I bought them you could get singles, doubles or triples. On some it was easy to straighten the LED legs and pull them out to fit other colors in.

I found some thin-wall, black coffee stirrers and cut one side on a bias and slipped them over the LEDs. The base is a LEGO piece.

They make good stand-ins until I get around to installing ones that are closer to scale. After I made these I began using red/yellow LEDs as yard trackage would probably use a medium aspect.

 The fellow that ran LED-Switch used to offer bi-color red/yellow but I'm sure you could find them from eBay or others. I sometimes use a single bi-color LED in series with a Tortoise.

Regards, Ed

If there was a red, yellow green stack

I could see it being used as a panel repeater, especially in N scale where anything approaching a realistic scale signal on a layout might not be visible

The (dis)Assembly

Here is what it looks like when taken apart - the shell is loosely held in place by minute tabs that snap into the holes as pictured in lower left corner of shell. The shell on the left fits over the body and helps align the LEDs. Pardon the quality of the pic, I chose not to do a white balance on the camera and shot by hand, macro mode, on a piece of white paper. As you can see, they are just standard LEDs with the leads bent in a sharp right angle. LEDs of similar size could be used instead. At the price, this is 20 green LEDs and 10 Yellow LEDs for $1.00 total.

LED dia. 0.11"

Shell width (Thickness) 0.16"

Shell height 0.60"

Shell depth 0.45"

gmpullman

That's what I had in mind !!    ,,,not prototypical, but i like the looks of it

 

Scale Sized:

I have some PRR position light dwarfs, too. They are closer to prototypical size but still slightly oversized and are quite tiny as you can see,

Similar to the ground throws, a little "stretch" in scale is tolerable. I'd actually like to find these PRR dwarfs in S scale just to make them a little more noticeable on the layout.

Regards, Ed