In New York, Roman Catholic officials have walked Pope Francis’ expected path through the National September 11 Memorial and timed it at five to seven minutes.

In Washington, studios for television news anchors are being erected on the roofs of the Catholic University of America.

In a quiet corner of Philadelphia, the buzzing epicenter of papal-preparation madness, there stands, carefully guarded, a lectern newly wrought of burnished black walnut, the product of thousands of dollars in labor and materials, that is just a stand-in for the one the pope will use.

Up and down the Northeast corridor, armies of organizers and event planners, stagehands and counterterrorism experts, tree pruners and translators, high school tuba players and even a few as-yet-unidentified celebrity chefs have marshaled to tackle an unimaginably vast set of tasks in advance of Francis’ arrival Tuesday.

Much has been made of this pope’s penchant for simplicity and understatement, his preference for personal ministry over pomp. But as those charged with procurement of wafers and the placement of metal detectors can attest, nothing is simple about a six-day, three-city, two-dozen-event papal trip that is a cross between a military operation, a diplomatic mission, and an arena-rock tour.

“The numbers, the scope of this makes me catch my breath, because it is so big, and at the same time, every little detail has to be just right,” said Donna Farrell, the executive director of the World Meeting of Families. Her Vatican-affiliated group is expecting more than a million guests at the concluding Mass for the Festival of Families on Sunday in Philadelphia.

The effort entails a series of water-into-wine transformations: box offices and concession stands at Madison Square Garden into confession booths, the Ellipse across from the White House into a half-mile popemobile track, Philadelphia’s Benjamin Franklin Parkway into a viewing corridor lit up like some oversize open-air sports bar with more than 40 Jumbotrons.

There are spreadsheets, and spreadsheets of spreadsheets. Behind a desk at the New York Archdiocese, the man who oversaw last year’s Super Bowl sits like St. Peter, poring over 80 categories of people who have sought tickets to papal events.

There will be traffic barriers sufficient to cordon off 4.5 square miles of Center City Philadelphia, and a two-hour pre-Mass extravaganza will be held at Madison Square Garden, featuring Gloria Estefan, Harry Connick Jr., and others, to get worshippers in the building early enough to allow the papal security machine to function smoothly.

In New York, the pope’s visit is timed to allow him to address the UN General Assembly, a mammoth, traffic-snarling security circus in its own right. (Dignitaries in attendance will include the president of the United States.) All told, said John Miller, a spokesman for the New York Police Department, up to 5,000 police officers could be required.

“It is really something that is multilayered on a level that we’ve never seen before, and this organization has planned and executed some of the most complicated visits, large events, and historic gatherings of any,” he said.

And as the pope whizzes about — by Shepherd One jet, helicopter, golf cart, and Jeep popemobile, accompanied by a 30-person entourage that includes translators, the Vatican police chief, and two Swiss guards (sadly for costumery fans, in plain clothes), shadowed at every turn by a credentialed media corps numbering more than 7,000 — his goal of accessibility and intimacy only creates more logistical challenges.

“With all the security, we still have to address the main purpose of this,” Miller said. “Which is, His Holiness would like to make contact, be seen by, enjoy the presence of, as many people as possible. So while we have to secure the visit, we also have to keep it as open and viable to allow the real purpose of his trip to flourish.”

Even the humble chair the pope will sit in at Madison Square Garden, built largely of plywood by immigrant day laborers in a two-car garage, caused a few headaches.

Steve Cohen, the production designer for the Garden Mass, said that when he heard about the chair, he thought, “This is all fine and good, but it’s got to work and it’s got to be comfortable and it’s going to be seen by a billion zillion people.”

Taking no chances, he arranged for a backup chair from a scenery company. He drove up to the garage workshop in Port Chester, north of the city, to see the laborers’ work. (To his relief, he said, it was “absolutely amazing.”)

When it comes to chairs, simple does not necessarily mean cheap, either. When the pope speaks at Independence Hall in Philadelphia on Saturday, he and four cardinals will sit on austere, lean-lined chairs made of cherry wood by the Thos. Moser Co. They list for $1,490 apiece, although Moser is donating them.

Some of the preparatory chores are stunningly prosaic.

“The piece of this that I would not have expected,” said Helen Osman, the communications secretary for the US Conference of Catholic Bishops, “is how much effort it takes to make sure that everybody’s luggage gets moved.”

Osman’s office commands 150 communications specialists who need to be everywhere the pope goes, before he gets there, and will travel by bus and train, not papal jet or motorcade.

“We have volunteers starting their days as early as 2 a.m., and they may be sleeping somewhere else that night,” she said. “They can’t be wheeling their bags around with them all day.”

Other duties are more sacred.

In Washington, the pope will canonize a saint for the first time on American soil, in an intricately choreographed ritual climaxing with the pontiff’s petitioning the Father, Son, and Holy Spirit, through the apostles Peter and Paul, to add a name to the divine catalog. The nominee is the Rev. Junípero Serra, an 18th-century California missionary.

For the occasion, said the Rev. Mark Knestout, a co-chairman of the Washington Archdiocese’s papal-visit liturgy planning committee, a small bone fragment of Serra has been shipped from California, and a vice-postulator has been summoned from Sacramento to read Serra’s biography into the record.

In another homespun touch, Washington’s archbishop, Cardinal Donald Wuerl, designed the embroidery for the vestments the pope will wear to Serra’s Mass.

Then there is the faux Lincoln Lectern, a near-exact replica of the one from which President Abraham Lincoln delivered the Gettysburg Address. The pope will use the original when he speaks at Independence Hall.

The original is at least 150 years old and too frail for the pontiff to lean on, so the Thos. Moser Co. was commissioned to build a metal brace for it.

The brace needed to fit exactly against the lectern. “The greatest catastrophe that could conceivably happen is for the thing to fall down, and for the pope to go with it,” said Thomas Moser, the company’s founder.

But the furniture makers could not borrow the original. Instead, they went to Philadelphia, took measurements and made a copy, using the finest black walnut, because there was a chance it would have to stand in for the original at the speech.

If all goes well, the imitation will be used during dry runs and then whisked away in favor of the real thing.

For some contractors who also worked on Pope Benedict XVI’s 2008 visit, the second time around has been a little smoother.

In 2008, Showcall, a Washington event-production firm, learned that Vatican officials were very exacting about the positions of the pope, the bishops, and the furniture at a Mass.

And that they use the metric system.

“We sent over our drawings,” said A. Blayne Candy, Showcall’s co-founder, “and all the measurements were in feet, and they came back with these confused questions on them: ‘But wait — 25? Twenty-five meters seems like it’s very far away.’” This year, Showcall drew up plans in meters.

In New York, where the pope will arrive Thursday, preparations are proceeding apace. The Central Park Conservancy is reviewing more than 2,000 trees along the route of the papal motorcade through the park for possible hazards.

The pastoral staff used by Pope Paul VI when he came to New York in 1965 will be dusted off by the archdiocese for Francis’ use. The pope’s quarters at the Vatican mission in New York shall be stocked, by papal decree, with still water and bananas and no other snacks.

Billy Joel agreed to shift a Friday night show at Madison Square Garden to Saturday to make way for His Holiness. (“What’s he going to say, no?” joked Cohen, who is also Joel’s production designer.) Joel even lent the papal production his sound and lighting gear. The archdiocese finished a $177 million renovation of St. Patrick’s Cathedral three months ahead of schedule.

Remodeling has also been fast-tracked at a well-worn Catholic school in East Harlem, Our Lady Queen of Angels, where third and fourth graders will share their work with a Very Special Visitor. A broken radiator in the anointed classroom and the circa-1956 floor that was damaged when the radiator gave out have both been replaced.

A trickier task, said the principal, Joanne Walsh, has been preparing the children to sing “The Prayer of St. Francis” from memory. Several lunchtime practices had not been enough to imprint the words in their young minds.

Walsh was not worried.

“They’ll sing from their hearts,” she said, “and it’ll all work out.”