What is the purpose of the black hatch on top of the hood near the cab on this BN SW1000?
http://www.rrpicturearchives.net/showPicture.aspx?id=642694
Looks like it's for accessing the "Engine Oil Bath Air Filters".
I went to the Fallen Flags website, where they have copies of various "shop manuals" for locomotives. I found one for the SW1500. On page 1-1, it has a drawing with reference numbers for various items.
Ed
I'm coming back to this topic a bit later.
First, the only online photo I could find that showed anything concerning that area:
You can see a grey box in that general area, though on the wrong side. Maybe that's the filter in the drawing.
I do note that this special access hatch is extremely rare on these engines. That gets me thinking that perhaps it's related to putting in a different kind of air filter, one that needed more/different access. I wonder at a regular (non-oil bath) filter that might need replacement, on occasion.
A quick look at photos shows BN 380 also had a feature like this. There may be others. Maybe the new hatch is only "extremely rare" on non-BN switchers.
I looked at BN SW1500's, and didn't see any. Maybe they're more "crowded" in that area.