Another great image from Then and Now, Images of Colorado and the West
Notice the rock formation at top left (a large rock with a smaller one on top of it). You can see the same formation in the 2015 photo.
Here is the description from the Facebook post:
Tracks of the Colorado & Southern narrow gauge in Platte Canyon. Early 1900's to 2015. The distance to Denver would have been roughly 28 miles by rail from this point when L.C. McClure took the original photo. Today, the most dramatic portions of the canyon are inundated by the Strontia Springs reservoir which was completed in the 1980's. When I visited in 2015, the water levels had receded just enough to allow me to stand out on the sandbar and capture this view.
Original photograph from the Denver Public Library Western History Collection.