I don't know, though "bug deflector" sprang to mind!
Notice that the one on the locomotive's left side has a straight bottom, the one on the right a curve to fit the contour of the nose: this makes me think it's a "field modification,' jury-rigged in railway workshops, and not a manufacturer-supplied option.
Could it be something as simple as an anti glare device ? It is in the right position to block out, reflect away, glare from the sun and improve visibility.
VIA's F40s have bug deflectors, so that would be my guess also.
MEC407 Moderator:
Pan Am Railways — Boston & Maine/Maine Central — Delaware & Hudson
Central Maine & Quebec/Montreal, Maine & Atlantic/Bangor & Aroostook
Providence & Worcester — New England — GE Locomotives