But, a 490 can pull more cars to Silverton than a 470. If the point is to convert on engine to oil to maintain operations during fire season, they will want the most powerful engine they can get to pull the longest train. Perhaps that's the line of thinking. Personally, I'll take oil over no steam.
I'm kind of surprised they aren't doing a dual diesel service--one from Durango-Rockwood to Cascade and another from Silverton. Silverton is king of left out in this temporary setup, but I guess it is only a couple of weeks. A bus from Durango to Silverton combined with a diesel ride up the canyon and time in Silverton to eat and shop would help the Silverton businesses.
Dave