Not much to go by here:
VIA_F9b by Edmund, on Flickr
I see two rectangular boxes on the roof itself, covered in plastic wrap, and two more, slanted, on the top of the end wall. The steam generator already has its combustion air intake, round, capped and screened vent.
Rapido Models mentions that they have included them on their models but they do not specifically say what the function of them is.
In this photo of VIA 6653 you can see a better view of the rectangular roof vents.
http://www.rrpicturearchives.net/showPicture.aspx?id=2621670
My guess is a re-routed exhaust stack for each steam generator. Note that there is no longer the round exhaust stack commonly found on the Vapor-Clarkson steam generator. Also note that there appears to be heat related corrosion on both those rectangular stacks.
Best guess, in order to comply with an environmental regulation additional treatment of the S.G. exhaust necessitated the re-routing of the exhaust. Other two boxes on the end wall are probably related to this mission as well.
Good Luck, Ed
I really can’t tell what the OPs talking about, but I think like Amtrak, VIA must have received it’s earlier locomotives and passenger cars. This would make me think the “boxes” are likely something added by CN or CP not VIA, though it is possible VIA made modifications.
Perhaps the OP could find a picture on the internet and identify these boxes to help forum members answer his question.
Regards, Isaac
I model my railroad and you model yours! I model my way and you model yours!
I ask for the two exhausts at the end of the roof.
Christian!
I am puzzled about your question. Are you asking about the winterization hatch that is often found over the end fan on the roof of the F-unit?
John
Hi,
I want to know - what are the boxes (each between every vent and edge of the roof)? Can you show me a picture/drawing to fabricate they?
Christian from Germany!