SOO SD60 Roof Items

[Jay]

I am in the process of taking my first adventure in trying to detail an engine of mine.  The items I am planning is adding fire cracker antenna, operating ditch lights & rotary beacon.  As I am looking at a drawing at http://www.sooline.org/publications/drawings/locomotives/SD60/SD60.jpg .  I see the items and placement I am looking to do.  But I am not sure of the item that is placed toward the very front of the roof before the antenna.  Can anyone help me with this item?  Thanks for the help as always!

[Santa Fe buff]

Take a good look at the roof.

http://content.answers.com/main/content/wp/en/thumb/8/89/300px-EMD_SD60_SOO_6022.jpg