Re: Re 6/6 11672 SBB
Is your question related to when the original headlights on the Re 6/6 (620) (and Re 4/4II) were converted to the new rectangular halogen headlights or when this specifically occurred for that particular locomotive?
The SBB ordered new material (Re 4/4IV (440) and RBDe 4/4 (560)) starting in 1982. These new units were delivered with halogen headlights instead of the original classic headlamps. It was decided that the final production of Re 4/4II (11372-11397) would also receive this new type of headlights. I believe that Re 4/4 11178 was used as a demonstration for the new livery and new headlight design.
It was then decided that all locomotives were to be retrofitted at their next scheduled major revision (R3).
This was the information that I could find for 11672:
As far as I can tell, 11672 finally received halogen headlights at some point since 2005. I have found photos from 2006 with the rectangular headlights, so I would assume that this would tend to support the 2005 revision as when this change was finally done. The locomotive has since also had air conditioning installed.