The westbound Zephyr heads west through a cut that is known as "Old Tunnel 17". When the Moffat Route was originally be built in the early 1900s, the tunnel presented a lot of geologic problems, includes frequent cave-ins. The tracks were rerouted around a shoofly outside of the tunnel. That shoofly is now beneath all the pine trees on the outside of the cut in this shot. Old Tunnel 17 was finally daylighted, and the tracks were moved to their current alignment, now moving through a cut instead of a tunnel.
While Tunnels 9 and 28 were daylight quite awhile after the route had been in operation, they retained their numbers. Since "Old Tunnel 17" had issues from the beginning of construction, at was ultimately bypassed, the next tunnel to the west was numbered Tunnel 17 from the start.
