heritage operations, who will oversee the restoration at the railroad's steam shop in Cheyenne, Wyo.

Dickens and his crew recreated the chalk inscription on No. 4014 when they began to move it.

Big Boys are 132 feet long, including the tender, which carried coal and water. They weigh 1.2 million pounds with a full load of fuel. They are essentially two engines under one boiler, with two sets of eight drive wheels, each set powered by two enormous cylinders nearly 2 feet across.

Big Boys are so big that the front set of drive wheels has to pivot separately from the back set to get around curves.

And they aren't just big, McCulloh said. They were engineered to reach 80 mph, even though the railroad never intended to run them that fast.The point was to fine-tune the locomotives so they stayed in balance at any speed and didn't beat themselves up with their own powerful forces.

"You get all that machinery to live in harmony," McCulloh said.

Their enormous bulk also hid some slick engineering, including a suspension system that kept the drive wheels pressed against the rails when the locomotive straddled hills or valleys.

Seventeen Big Boys were scrapped when they were pulled from service, but eight survived and are on display around the country. Union Pacific chose the 4014 for restoration because it spent more than 50 years in the friendly climate of Southern California, at the RailGiants Train Museum at the Los Angeles County Fairgrounds.

The museum took good care of the locomotive, Dickens said, and many of the original