The California Zephyr Amtrak train will use an alternate route through Wyoming for 32 days this summer, instead of its normal route through Colorado, Amtrak announced Tuesday.

The train will detour onto UPRR trackage through Wyoming, a route that passenger trains have not traversed since 1997, according to Amtrak.

Scheduled maintenance on the 6.2-mile-long Moffat Tunnel under the Continental Divide necessitated the detour. The Tunnel opened in 1928 after four years of work and is the keystone of the Denver to Salt Lake rail line -- allowing trains to traverse Colorado year round.

The periods of the detours are June 8-15, June 23-30, July 8-15 and July 23-30.

Service to Fraser-Winter Park, Colo.; Granby, Colo.; Green River, Utah; Helper, Utah and Provo, Utah, will be suspended on the days of the train