Today’s scheduled move of the “Big Boy” has been put on hold.

The Museum of the American Railroad announced Saturday that the planned transfer of the Union Pacific 4-8-8-4 Big Boy from Fair Park to Frisco, TX, was cancelled because of a derailment along the route in which the locomotive is to be escorted. A new date has not been announced.

“We regret any inconvenience this may cause to our stakeholders and supporters,” said a statement from the museum on Saturday morning announcing the delay. “We are very appreciative of all the efforts put forth by the local railroads as we continue to move the collection from Dallas to Frisco.”

MAR is making the move with assistance from the Dallas, Garland and Northeastern Railroad and BNSF Railway.

On Saturday, MAR hosted museum supporters, volunteers and media members for an “exercising” of the Big Boy and photos.