This little board is intended to make life a little easier when adding marker leds to a hood diesel. The leds and load resistor are all soldered to the board, along with an optional diode if the power source is AC, such as in a dummy engine. It includes two optional led pads on one end so as to accommodate narrow and wider hood diesels. For a narrow hood engine you would simply chop off the extra length with a dremel. Any color and any size leds can be used, including 1.8mm flat or round top, 2mm flat or round as in the pictures, 3mm or 5mm.
Here it is installed in a narrow hood switcher:
Here is the completed engine. Yah I know, switchers don't have marker lights. Too bad, it was sitting there handy on the layout. My layout, my rules.
You could also use this board for dual led headlights, or caboose marker lights, number board lights, etc. It just makes the led wiring in an engine much easier to deal with. I have pre-built a few of them so they are ready to quickly drop in when the need arises.
Attached below is a .pdf file of user notes, and the gerber files for anyone who may want to order up their own boards.