The son of Disney’s original Imagineer, Roger Broggie Jr. began working for the man he called “Uncle Walt” as a boy in 1950 when he tended the backyard railway at the studio mogul’s Holmby Hills home.

Broggie was 11 when he and his younger brother, Michael, started serving as the crew for Walt Disney’s miniature steam-engine railroad. The siblings pulled cars out of storage, dusted them off and rolled them down the track to a “Valley” called Yensid – “Disney” spelled backwards.

“We had chores,” said Michael Broggie, whose father helped Disney build and install the train. “As Dad and Walt got the engine ready, we would fill up the tenders with coal and water.”

The rarefied pastime lasted until 1953, when Disney shut down the train that neighbors had lined up to ride. The small-scale attraction had served a historic purpose, helping to inspire the creation of Disneyland.

At 18, Roger Broggie Jr. joined Disney’s company as an apprentice in the machine shop managed by his father, Roger Broggie Sr. The junior Broggie became an audio-animatronics pioneer, making key contributions to such attractions as Great Moments With Mr. Lincoln, the Enchanted Tiki Room and Pirates of the Caribbean.

He died Dec. 11 at a medical center in Bend, Ore., from complications of a head injury sustained when he fell while working on a float for a parade near his home in LaPine, Ore. Broggie was 73.

His family announced his death last week.

“Roger was one of the finest mechanical craftsmen who ever worked for the company, an absolute master,” Marty Sklar, a retired longtime Disney executive, told The Times last week.

While helping to build several Disney attractions for the 1964 New York’s World Fair, Broggie became known for his hands-on technical wizardry while helping to create the now-familiar form of Disney robotics known as audio-animatronics.

Making President Lincoln lifelike for Great Moments, which debuted at the fair, “was particularly challenging because no one had made a figure move like that before,” said his brother Michael, a Disney historian.

All of the electronic gizmos had to be contained within the framework of the sculpted head, a task that fell to Roger Broggie. An “interesting cheat” solved the problem, according to Jim Hill, who has tracked Disney history for more than 30 years. The wig was stretched out on the Lincoln head to make room for the bulky first-generation parts.

For the Enchanted Tiki Room, Broggie did an exceptional job building a flock of mechanical exotic birds, Sklar said, and his technical wizardry helped persuade Disney to open the Tiki Room in 1963 as a full-fledged attraction instead of a restaurant.

Broggie also played a lead role in the development and installation of audio-animatronic figures in Pirates of the Caribbean and the Haunted Mansion, which both opened in the late 1960s.

Disneyland pays homage to Broggie on Main Street, where his name appears in the window of the Little Gremlins Mechanical Toys shop.

He was born April 12, 1939, in Los Angeles. His father and mother divorced when he was 12, and he spent his teen years watching Disneyland evolve, playing at the park as a construction site and test-driving cars for the Autopia.

“They gave the first two prototypes to the Broggie brothers to drive around the lot,” according to Hill. “They said, ‘If they can’t break them, the kids at Disneyland can’t break them.’”

Of the eight Broggies who eventually worked for Disney, six have been Imagineers. Roger Broggie Jr.'s son, Garry, runs the machine shop once operated by his grandfather, who was instrumental to the development of Disneyland’s railroad.

When Disney made the 1969 film “The Love Bug,” the junior Broggie’s mechanical fascination with cars helped him build “something like 17 Volkswagens” to play the Beetle of the movie’s title, his brother said. Each car was made to do a different trick, such as flying or floating.

In the late 1970s, Broggie founded the Only Animated Display and Design Company with two other former Imagineers. Their projects included developing attractions for Disney and other theme parks and creating mechanisms for Rose Parade floats.

His technological sleight-of-hand also helped bring a memorable end to the 1984 Summer Olympics when the “spaceship” Broggie helped fabricate appeared to hover over the Los Angeles Coliseum and “converse” in light and sound. The contraption was actually suspended from a helicopter.

The low-key Broggie “was a really selfless guy,” Hill said. “How he died was so in character – doing volunteer work on a Christmas float.”

Broggie is survived by his wife, Marilyn; five children from his first marriage, Scott, Garry, Richard, Robert and Deborah; his brothers, Michael and Brian; 15 grandchildren; and two great-grandchildren.

A memorial service will be held at 11 a.m. Feb. 2 at Grace Baptist Church, 22833 Copper Hill Drive, Santa Clarita.

valerie.nelson@latimes.com