An Interesting Photo

I bought this slide a while ago on eBay. It has a very interesting subject - a Canadian Pacific car on the Reversing Falls bridge in Saint John on July 22, 1967. The seller labelled it as a transfer caboose, and it may well be that. Does anyone know what kind of car CP 402472 was? There is small lettering on the car that says "cabin car".

Click on the image for a larger view.