Homestake Pass and the US Forest Service edit

The existing article on Homestake Pass refers to a purported agreement between the Northern Pacific and the US Forest Service regarding the right of way over the pass. Since Homestake Pass was completed in 1890 (per The Butte Short Line by Bill and Jan Taylor) and the Forest Service came into existence in 1905 (per World Book Encyclopedia), how could such an agreement exist?

Jim Woodward