Like the legendary muralists of centuries past, Ralph Gilbert had to please his bosses when he was hired to paint six murals for Union Depot in downtown St. Paul.

Think Tiepolo, summoned from Italy by King Charles III of Spain to paint the palace ceilings in Madrid in 1762.

Or Michelangelo ordered onto the scaffold by Pope Julius II, who wanted some fresh frescoes for the Sistine Chapel in 1508.

Neither of those guys had much say about what they were to paint. Nor did Gilbert.

Tiepolo’s task was to glorify Spain. Michelangelo’s was to magnify God. Gilbert’s more modest job was to evoke the role of railroads in the settlement, expansion and history of Minnesota.

Two years and many drawings and studies later, the Atlanta-based artist watched as his work was installed last week in the skylit waiting room of the refurbished depot.

Starting Thursday — with an evening event that includes a tour of the new murals — the nearby Minnesota Museum of American Art will showcase about 35 paintings, figure studies and scale models for Gilbert’s paintings. The show runs through Dec. 7.

Gilbert’s $150,000 commission is the last of 10 new artworks at the depot, listed on the National Register of Historic Places for its handsome neoclassical facade and 1920s interiors. The building’s four-year, $243 million renovation was paid for with federal, state and county money, including $1.25 million for art by local, regional and national talents.

Six themes

Picked from a pool of 69 competitors, Gilbert was given his marching orders in the form of five themes suggested by the Ramsey County Railroad Authority. The sixth topic was his choice.

Specifically the murals had to reference the railroads’ impact on the Dakota tribes and their land; the importance of railroad jobs for African Americans, especially in St. Paul’s Rondo neighborhood; the “orphan trains” that carried an estimated 250,000 homeless New York kids to new lives, often on Midwestern farms; immigrant settlers arriving, and, finally, soldiers departing in wartime. With the advice of a depot historian, Gilbert picked the U.S. Postal Service and its ties to the railroad as the sixth topic.

While some artists might chafe at so much direction, Gilbert welcomed it. Articulate and soft-spoken, he shies from comparing his work to that of the Old Masters — “that would be incredibly presumptuous” —but he knows art history and enjoys discussing it.

“I don’t take the attitude that the only good art grows out of a self-reflective, narcissistic impulse,” Gilbert said as workers moved scaffolding and hung panels. “Nobody ever says, ‘Titian would have been so much better if only he had done his own work.’ Projects like these are yours to succeed with or fail at. And ultimately these reflect who I am, and not just the suggestions of a committee. This is my own work.”

Evocative history

Painted on panels of fiberglass-faced honeycomb aluminum, the murals are realistic but not overly detailed. Their predominantly blue and beige tones complement the waiting room’s blond brick walls. Shifting in scale, the figures are archetypes rather than portraits of particular individuals. Vignettes suggest places, times and moods without documenting specific events.

“I wanted something more evocative than illustrative because I’m an artist, not an illustrator,” said Gilbert.

Even so, the murals do convey episodes in Minnesota history. The African-American mural is especially poignant as it alludes to the rail jobs — sleeping-car porter, dining-car waiter, even shoeshiner — that provided decent wages at a time when entrenched racial prejudice limited opportunities for blacks. The scenes flank a roadway subtly marked Hwy. 94, the freeway that essentially destroyed the primarily black Rondo neighborhood decades ago. At the top, three figures in graduation caps and gowns symbolize the community’s hopes and dreams.

“The committee was very concerned that I understand the social implications of what I was doing,” Gilbert said. “It was important that even people doing very difficult jobs were shown doing them with pride and aspiration.”

At 16 feet tall and 6 feet wide, the depot panels cover a lot of space, but they’re not the largest on Gilbert’s résumé. That title goes to a 40- by 20-foot barrel-vaulted ceiling he finished in 1997 for a visitor’s center at the Piedmont Park Conservancy in Atlanta. A colorful scene of skateboarders, athletes, strollers and others enjoying a glorious summer day under a sunny sky, the mural was especially challenging because it had to be painted on a curved surface in a historic building.

That, of course, raises the inevitable question inspired by the 1965 epic film “The Agony and the Ecstasy,” starring Charlton Heston as Michelangelo.

“So, did you paint it lying on your back?”

“Only Charlton Heston worked on his back,” Gilbert said, with an eye-roll hinting that he might have heard that question before. “Michelangelo stood up, and so did I.”