tunnel on Rio Grande RR

Going through tunnels on freight trains is interesting, to say the least. The one above is about 10 miles west of Dotsero, Colorado, on the Rio Grande line between Denver and Salt Lake, where the tracks run alongside the Colorado River. It was July 1981 and I was on my way back west from Denver when I took this picture. The engines are the helpers on the rear, not the head end power. The tunnels along here are just blasted rock on the inside — not concrete-lined like so many others.