Right the first time. It says caboose on the side. In fact all the cars in the train were lettered DSP&P
As for the 1886 date of the photo, a firm maybe. A couple of the box cars have DSP&P Phase 2 lettering, which was introduced in the summer of 1885. Could be 1887-1889. But believe this to be less likely due to the clean lettering on the cars
From newspaper reports, Beaver Brook seems to have experienced some sort of washout or flood about every other year.
Using these dates as guide posts, I'm thinking that if I collate all of my notes, I might be able to assign some dates to the various photos
Ron Rudnick