I just updated the thread title... I thought 401 was a SD9, but realized on double checking its an SD7. Turns out the class lights design is different on most SD9's compared to the SD7; more of a 'frog eye' shape on the 9 while the 7 has the flat access door. Interesting spotting feature.
Those are access doors for getting at the back of the lights. It DOES look like NN intentionally propped them open. You can see the little bar. But there are later photos of that engine with the doors shut.
I wonder if they were flirting with some kind of warning light--maybe put a flasher circuit on those.
Or maybe they wanted "augmented lighting" facing forward. Hard to imagine class lights being much of an augment, though.
Interesting!
Ed
So here is an interesting photo I ran across taken in Ely, Nevada in 1971 showing Nevada Northern 401 with a Rio Grande gondola in tow. There is one interesting detail though which caught my eye in the shot...http://www.railpictures.net/viewphoto.php?id=302403It looks like the class lights have been popped out from the hood. Talking with a fellow railfan it sounds like this was a pretty standard feature on EMD products, but I have never really seen it in use before. Does anyone know of any other railroads which ran locomotives with those mini-pop out frames for the class lights? Any cases of model railroaders who have modified their locomotives to have the lights out like this?