Hi Greg,
While there are a couple of spots on the run from Chama to Cumbres Pass where access is definitely more convenient by train, the vast majority of shots can be taken from the highway, so if one is looking for say 4-5 decent locations, a chase is the best way to accomplish it in my experience. The railroad schedule really doesn't permit them to stop more than once or twice on the hill, without affecting the schedule of the revenue passenger train.
In the case of the latest charter, the plan had been for 4 total run-bys:
-Chama Stock Pens
-Chama Water Tank
-Orgasm Curve
-Hamilton's Point
The reality was that the stock pen shot was done just a little too early, so there were shadows all over the train and the environs. In addition, parking/access was completely uncontrolled, so it was difficult to impossible to get a clean shot without cars, people and tripods. The area around the Chama Water Tank presented similar problems. The only run-by we did on the hill was Orgasm, and the folks on the highway got better shots, due to their elevation. Hamilton's was skipped entirely due to schedule.
By the time the train reached Coxo, there were perhaps 100 or more chasers poised at the crossing, on Kodak Rock, on Roger's Rock, and aboard the Goose on Windy Point. It was a grand show as the train came out of the woods.....for everyone but the 40 or 50 of us who paid over $2000 each to finance it.
I do at least half a dozen charters per year, contributing as much $$$ to the cause as just about anyone I know. I personally couldn't care less what the chasers get, as long as they stay out of way. It is only when I'm paying the bill and the chasers are the only ones getting the good-light photo opportunities that I begin to get a bit grumpy.
/Kevin