As you read these words, the new Francis Scott Key Bridge is being built.

Not out on the Patapsco River, where vestiges of the old structure linger as a quiet reminder of its demise one year ago, but in conference rooms and with computer models, by task forces assigned to niche parts of its construction.

Overseeing it all is James Harkness, the Maryland Transportation Authority’s chief engineer who has been thrust into the largest project in the department’s history.

Before construction crews can get to work on the new span and its roadways, officials must expedite a design process. Roughly 150 engineers work on the project any given week. Their local headquarters? An office building in an Anne Arundel County business park.

Constructing a structure requires a series of problem-solving exercises. Engineers get in a room, discuss options, advantages, disadvantages, rinse and repeat. With an expansive team — engineers are based in at least seven states, as well as Europe — each person brings specialized bridge-building experience to the table.

“That’s the part I enjoy,” Harkness, 47, said in a recent interview, “seeing that come together.”

One year ago, a 100,000-ton cargo ship, the Dali, lost power at the most untimely moment, plowing into a crucial support pier of the Key Bridge. The span’s swift collapse killed six construction workers and blocked the shipping channel to the Port of Baltimore for months.

But even as massive chunks of bridge debris remained in the water, rebuilding efforts began.

Typically, constructing a new bridge of this scale would require years of preparation: From contemplation to completion, building a new Harry W. Nice Memorial Bridge over the Potomac River took 16 years. A potential replacement for the Chesapeake Bay Bridge has been studied for years and is still probably at least a decade away.

The Key Bridge is expected to be completed in 4 1/2 years, by fall 2028. Its estimated price tag — which, at $1.7 billion to $1.9 billion, is three times that of the (smaller) Nice Bridge — is federally funded.

The speedy, massive undertaking is costlier than anything the MDTA has previously built, and is the largest project of Harkness’s career.

The son of an architect, Harkness grew up in Philadelphia, had an early interest in math and physics and studied civil engineering at Penn State University. He worked in the private sector in Baltimore before becoming the city’s traffic engineer, tasked with analyzing and improving Baltimore’s network of roads.

“I gravitated toward that public side, just because I really liked the idea of how transportation projects benefit so many people,” he said.

The City of Baltimore manages some smaller bridges and, once Harkness joined the state transportation authority in 2014, he assisted with major bridge projects, including the construction of the Nice Bridge.

But few engineers have worked on an emergency response — and accelerated construction — like the Key Bridge.

Harkness’s regular commute from his Carroll County home to the authority’s engineering offices in Dundalk took him over the Key Bridge regularly. It often provided a memorable morning vista.

“About this time of year, the 7 a.m. sunrise over Tradepoint Atlantic, that area, used to be one of my favorite views,” he said.

Within minutes of the Dali striking the bridge, Harkness was notified.

Authority officials plan for emergency scenarios with tabletop exercises, but the magnitude was not something they had prepared for, he said.

The search-and-rescue efforts and the long process to pick up pieces from the Patapsco River began immediately. There were risks to assess, such as ensuring that the remaining structures weren’t at peril of falling.

In a matter of weeks, though, the MDTA also had to come up with a budget and preliminary timeline for the replacement.

Never, authority officials said, did they consider the possibility of not rebuilding the span — a pledge also made by then-President Joe Biden, Gov. Wes Moore and other elected officials.

As the owner, the transportation authority is ultimately responsible for the bridge rebuild. But it contracted a team of several companies, led by the national construction giant Kiewit, as the builder. Some of those engineers work remotely and visit Maryland occasionally, but others were required to relocate to Baltimore.

“They do uproot a little bit and come here to Maryland for a while,” Harkness said.

As predicted by experts, the authority opted for a cable-stayed bridge, a type of span that has grown in popularity over the past three decades for its affordability and construction speed. Towering pylons will be built with cables fixed to them; those cables, in turn, support the roadway.

The bridge’s main span — which determines how far the bridge’s two piers are from shipping traffic — will be one of the longest in the United States. But there are scores of larger spans elsewhere in the world.

There is an “honor and privilege” in building a bridge of this size, said Habib Tabatabai, a structural engineer at the University of Wisconsin Milwaukee who has studied cable-stayed spans.

“It is not a trivial project at all, by any means,” he said of the rebuild. “It is a significant structure.”

Preconstruction activities, such as soil analysis, began earlier this year, and information gleaned through that process will inform Harkness and the small army of engineers as they continue designing the bridge. For example, engineers still have not finalized the type of pier protection the new structure will have.

Meanwhile, Harkness is the chief engineer for the authority — not solely the Key Bridge — so he has other responsibilities. About two-thirds of his day-to-day work is focused on the bridge rebuild, he said.

Much of it revolves around computer models.

“Engineers love models. We have models for everything,” Harkness said. “If we can model it, we’re going to try and model it.”

Mostly, that calls for computer programs. But it also requires some physical structures, such as a several-foot-long prototype of a bridge segment that has been tested in a wind tunnel in Canada.

That’s just one tiny component of the rebuild. To make their goal manageable, engineers have broken into a variety of task forces, each focused on a single segment of the project.

“It’s the old, ‘How do you eat an elephant?‘” Harkness said. “‘One bite at a time.‘”