I guess there has been a change to the steam excursion schedule for the golden spike celebration. 844 is no longer coming out this weekend but will be double heading with 4014 on May 4th.
Here's the email excerpt that was forwarded to me from a friend.
"Final touches on its paint job are being applied and the last necessary tests are being conducted.
To ensure the Big Boy is ready for its big debut, No. 844's whistle-stop tour that was scheduled for this Saturday and Sunday, April 27-28, has been cancelled. Instead, No. 844 will double-head with No. 4014 from Cheyenne to Ogden on May 4 after the 9:30 a.m. MT christening ceremony.
This new schedule will give the UP Steam Team more time to complete final preparations for No. 4014.