Greg, the Grand Canyon Ry. has very strong ridership, that has been steady at between 150-175,000 riders for several years. It was one of the few Western roads that didn't see a dramatic drop since 2000. I think it has outstripped the D&SNG numbers since the late 1990s. Sad to say, the D&S peaked in the early 1990s and it ceertainly is not what it was since. No plans are in place to reinstate a 4th Silverton train.
It is not clear why neither the C&TS and the D&SNG have not recovered from the 2002 disaster, but a combination of poor promotion from state tourist boards(Governor Lowbeam in Colorado signed a cut in tourism promotion a few years back), expensive gas, food,lodging and being off the beaten track has hurt the two roads.