The Pengra Pass route was built to provide trains running between Eugene and California with a cheaper and otherwise more practical option than to follow the older Siskiyou Pass route, which runs south from Eugene and over Siskiyou Pass to California. As a result, the Siskiyou Pass route was rendered nearly obsolete. In 2008, a landslide in the area shut down rail traffic for 105 days, which forced Union Pacific trains to make lengthy detours and Amtrak to halt services between Eugene and Sacramento, severing a key west coast rail link. In 2011, no trains had used the Siskiyou Pass route in almost a decade. By 2015 however, that line was reopening to relieve I-5 of local truck traffic. On May 29, 2018, one of the tunnels, known as Tunnel 11, caved in during scheduled maintenance work, shutting down rail traffic for 3 weeks. Union Pacific rerouted their freight trains running between Northern California and Portland through a lengthy detour, while Amtrak service did not operate between Eugene and Sacramento (initially between Eugene and Klamath Falls, with a bus bridge between the two points).