The Big Boy locomotive left North Platte at 10 a.m. Thursday, two hours later than planned, after waiting for the all-clear signal from the Kearney and Gibbon areas, where flood water threatened the tracks.

Big Boy, the biggest working steam locomotive in the world, pulled into a siding in North Platte around 3 p.m. Tuesday, next to Front Street downtown, where it was serviced. It was scheduled to depart at 8 a.m. Thursday.

But the schedule became uncertain because of floodwater, Union Pacific said Wednesday.  The Kearney area was inundated with 9 inches of rain overnight Monday. Floodwater cut off and paralyzed part of the city.

The big locomotive could be seen from the shoulder of Front St. in North Platte. Visitors were restrained from getting closer by a chain link fence.

The Big Boy, No. 4014, is headed to Omaha and then on to Illinois in a trip commemorating the completion of the transcontinental railroad 150 years ago.  The locomotive is scheduled to return to North Platte Aug. 5, during the annual Rail Days celebration, when visitors will be able to see it up close.

Twenty-five Big Boys were built for Union Pacific, the first of which was delivered in 1941 to handle the mountainous terrain between Cheyenne, Wyo. and Ogden, Utah, carrying vital freight during World War II.

Of the eight still in existence, No. 4014 is the world’s only one operating and still owned by Union Pacific. Following more than two-and-a-half years of restoration, No. 4014 recently traveled to Ogden for the anniversary celebration of the transcontinental railroad’s completion, where it met the Living Legend No. 844 nose-to-nose, recreating an iconic photograph taken May 10, 1869, when the last spike was tapped into place at Promontory Summit, creating the first transcontinental railroad.

On Aug. 3-6, the Rail Days celebration will be held to synchronize with Big Boy’s stop on its way back to Cheyenne. Rail Days will begin the weekend before the train arrives.

On Saturday, Aug. 3 at Cody Park, there will be free rides, inflatables, swimming, food, vendors and more; including a Clifford the Big Red Dog photo booth, organizer Kirsten Parker of the Golden Spike said.

Big Boy will arrive Monday evening, Aug. 5. It will be open the next day to the public, along with a special “experience car” filled with Union Pacific history.