CSX operates four road trains per day, Q620 (south), Q621 (north), B753 (south), B756 (north), and Woodard, Watertown and Massena each have at least two locals that usually operate every week day. Q620/Q621 operate between CN in Montreal and Selkirk Yard, these are CN runthroughs and don't typically do any switching along the way, except in Massena where Q621 drops cars for Alcoa and picks up traffic bound for Montreal, and Q620 has some cars for Massena that they drop. These trains were rerouted onto the D&H a few times in recent years because of trackwork being performed on the St. Lawrence Sub, but they are back now to their usual route. B753/B756 (used to be Q623/Q622) operate between Massena and DeWitt, B753 takes cars from Massena, Watertown, and Woodard that have to go to DeWitt, B756 takes cars from DeWitt that go to Woodard, Watertown, and Massena, this also includes cars that are going to Beauharnois, Quebec.
There are a few extra moves on the St. Lawrence Sub, Fort Drum gets many coal and coke trains throughout the year and military vehicle trains also operate pretty frequently. Most of these move overnight between Syracuse and Watertown, they are normally moved during daylight between Watertown and Fort Drum by one of the Watertown based locals, typically B778. Recently grain trains have been operating from Syracuse to Woodard, then to the new ethanol plant in Fulton, I think they have been getting one a week, traffic in and out of the plant will probably increase significantly once the plant is fully operational.
I'm not 100% positive on this but I believe traffic has increased slightly from when Conrail owned the line, mainly because of increased Fort Drum traffic and Fulton ethanol plant traffic. Also I think what's now B753/B756 used to only operate five days a week where they now run everyday. As far as power, Fulton recently has had a slug set assigned to the yard, there also is at least one unit assigned to Woodard, two for Watertown for B778 and B779, and at least two local units for Massena, probably more for one of the other jobs that run up there. B753/B756 usually have any pair of CSX units, same with Q620/Q621, sometime more power if needed of course, foreign power shows up on rare occasions. CN power can be seen bringing Q620 into Massena and heading back to Montreal on Q621, CN power is not usally seen south of Massena anymore, though sometimes they slip through. Fort Drum trains sometimes provide some color, this year has seen a couple KCS/TFM pairs on vehicle trains, and a BNSF pair as well, and CP/SOO power on a coke train.