The Gull wing refers to the very top of the cab. Its easier to explain through pictures so take a look at this picture.
See how the the cab slants right by the number boards at a steep angle and then flattens out again. This is the gulllwing cab http://www.locophotos.com/PhotoDetails.php?PhotoID=68833
And this picture the cab takes a lesser angle thn the previous cab, and doesn't flatten out at the end. http://www.locophotos.com/PhotoDetails.php?PhotoID=93199
The gull wing was at the request of ATSF, there were some clearance issues on some coal loadouts. The bevel allowed the locomotive to clear the chutes, and remain on the point of the train while it was being loaded.
The gull wing was at the request of ATSF, there were some clearance issues on some coal loadouts. The bevel allowed the locomotive to clear the chutes, and remain on the point of the train while it was being loaded.