Steven, I decided to ignore passenger ropeways because I wanted to keep the article ...eh... short. You should check the second link listed in the bibliography, "Hercules Aerial Tram Mobility Study & Report". It was of great help for my research, even though it investigates passenger ropeways, not cargo ropeways. The researchers conclude that passenger ropeways have a large potential in the US. One problem is that most traffic engineers don't even know them. The second problem, however, are insurance costs, which "tend to be so high that they cancel the cost benefits of energy savings and lower capital costs". That is not a problem for cargo tramways.