The small 2mm marker led boards posted earlier in this category can also be easily used for red-green directional leds on any can motor equipped engine; that change color with engine direction change. All you need besides the boards is a stash of 2 or 3 mm bi-color 2 pin diodes.
The picture and video shown below are using 5mm leds, which is all I have on hand at the moment, but 3mm bi-color are easy to find and more realistically sized. The direction change is done by attaching the two wires to the power connections of the can motors in each end of the engine, one alternately from the other. The idea of course is to get each end leds green when moving in that direction, and red when moving the other direction. You could also set them all up to go green when moving forward and red in reverse.
The original 2mm Marker led topic is;
A Handy Little PCB for Adding Marker LEDs to a Hood Diesel
It has all the info and gerber files for ordering some boards. Note that its the first thru-hole DC R1.0 gerbers you want; not the later smd AC version. I tested these using 12vdc and 470R load resistors in the boards as you see. They work great.
2mm bi-color 2 pin leds are not very commonly available it seems. I found one German source who wanted 9 Euros for 10 leds, and 30 Euros to ship them! I gracefully declined. Couldn't find any on ebay or AliExpress, but they may be out there somewhere. We can only hope that they become more readily available.