Hi Greg, I really didn't mean to bash the zoom lens. I think they have improved a lot over the years. I carry at 24-70, 50-300 and a 15 prime I use mostly for landscape photos. When I shot 35mm I had mostly primes lenses. Over all I have been shooting for 52 years and I don't have a lot to show for it as a fire in 2002 took care of most of the photos.
Lighting can be a problem in RR photography as you have to shot many times in the middle of the day. When the UP 4014 Big Boy was traveling back to Cheyenne, I followed it from Morgan, UT to Bitter Creek, WY. The lighting wasn't the best but I came away with a few good shots. It would have been nice if Big Boy would have been on point instead of sandwiched between two diesels.
Like you, I think composition is very important in getting a good photograph. During C&TS work session I attended we would normally quit what we were doing and watch the morning train depart. I would get my camera and shot a few pictures.
Keep Shooting,
Sandy