What is that ?????

[FCIN]

That's a hanger for carrying an EOT. At least that's what several NS crewmen say is its purpose. Have seen them on a lot of NS engines, but mostly on the older locomotives, such as C40-8/9's, SD60's and SD70's.

Based on some photos I've seen taken at Railfest, locomotive in question might be NS 6332 an SD40E.