How to identify Geeps and or SD's from one another

[nycentral57]

Do like I do when I see a locomotive and I can't ID it.

I write down the road number and look it up online.

For example; I typed into Bing "Norfolk Southern 5113" and it delivered this link RailPictures.Net Photo: NS 5113 Norfolk Southern EMD GP38 ...

This method has yet to fail me.

I also recently have learned that trick and your right it never fails.