How many cars can Hawaii #12 pull up the Loop?

There has been a lot of conjecture, on this board and other sites, about the pulling ability, or lack there of, of the steam locomotives that will make their way to the Georgetown Loop in the near future. Having nothing else to do this morning (not really) I set out to see if I could answer that question based upon known facts. So, for your flaming pleasure, my crude analysis is presented below:
According to "The Colorado Road" C&S #9 has a tractive effort of 16,301 pounds while C&S #60 has a tractive effort of 15,810 pounds and C&S 74 has a tractive effort of 21,170 pounds.
According to a 1930's C&S tonnage rating roster for the South Park line, #9 & #60 were rated for 110 tons on the west side of Boreas Pass (Breckenridge to Boreas is a fairly steady 4% climb so tonnage ratings for it should relate well to the Loop) and #74 was rated for 145 tons on the same climb. Note that to the C&S the 500 pound difference in tractive effort between #9 and #60 made no difference in the tonnage ratings. For comparison, C&S 54, which had a tractive effort of 13,463 pounds was rated at 75 tons for this climb.
D&RGW drop bottom or high side gondolas weigh 11 tons each empty, Add four tons for 40 passengers who each weigh 200 pounds and you get a total weight per car of 15 tons. Typical narrow gauge passenger cars (ie D&RGW coach 280, the GLR's Tahoe and the C&S cars in the Crystal Palace in Silver Plume) weigh some 22 tons each empty.
Assuming that Railstar uses drop or high side gondola based cars (we know that at least six of their cars will be as such) and based on the above tonnage ratings the locomotives could pull the following number of cars over the Loop:
C&S #9 or 60; 7 cars at maximun tonnage, 5 or 6 would be better.
C&S #74; 9 cars at maximum tonnage, 7 or 8 wpuld be better.
Hawaii 2-6-2 #12, with its 15,000 pound tractive effort would be close to #9 in pulling capacity. Even discounting its tonnage rating 15 tons less than #9, it should still be good for 5 or 6 cars.
Using actual passenger cars, or newly built cars that weigh as much as the old coaches, would cut these car ratings in half.
Seems to me that Railstar's statement that #12 could pull 6 cars is based on sound facts.
Also, keep in mind that up until 2003, GLR ran 6 trips per day with a 7 or 8 car train, depending upon the time of year. Railstar could come very close to this capacity with a 6 trip schedule and a 6 car train.
Jason Midyette