I'm currently working on the SD40-2 which will replace the core version in 2012. It's gonna be snazzy!

What I'm interested in is the lights located above the front trucks as I know very little about them. Are they only on the front? Are they specific to certain companies or certain batches? Where exactly are the lights produced from? Any and all information will be helpful, I don't even have a name for them to research so it's proving a little trying.
