The bottom line on this discussion is that SNC people are working very hard to create good jobs in a region that really needs them. There is a lot of useful material in Tahawus that is a bit of a blight on the landscape. Pulling it out by rail would be helpful and using rail would be environmentally more friendly.
Regardless of what the S&NC is doing right now operationally, they are fully capable of running the same size trains from Tahawus to Saratoga that the D&H did when they were moving ore. Very little has changed. I heard that a 10 car loaded train was brought down from Tahawus this past week.
Back when CP still ran their trains to New York City, CP was moving a lot of stone from Saratoga and Comstock down to the NY metro area. So the economic viability is there in theory.
The hoppers being used are ex DM&E 3 bay hoppers. I would assume they were excess assets CP was looking to unload as CP is in the process of getting rid of excess assets under the current management. They were probably a good deal for SNC. These are pretty large hoppers so they will not be filled very much with respect to hauling stone. Just like trucking. You can only put approx. 40,000 lbs in a 53 ft trailer. With feathers the trailer will cube out way before weighing out. With heavy machinery, the trailer might be half full when it weighs out.