There is no cell coverage in the canyon, make sure to download your coordinates offline before heading out!
This is a semi devious log only cache, hidden at the monument of the hero railroad engineer William G. "Billy" Westall. On the afternoon of August 28, 1898 Westall who worked for the Denver, South Park and Pacific Railroad was headed back to Denver with 450 passengers. Upon rounding the blind curve around dome rock, he noticed the tracks had been washed out by an earlier storm. Billy managed to slow the locomotive enough that only the engine derailed, saving the passengers from harm at the cost of his own life.
Learn more here: William G. "Billy" Westall
Update: Thanks to Cajrrman for sharing this information about the monument, that used to house a cache and was subsequently archived a decade ago: A Hero of the South Platte