Two years down and about two more to go.

Hartsfield-Jackson International Airport is just past the mid-point of an intricate project to extend its Plane Train, which is crucial to the world’s busiest airport’s strategy to handle even larger crowds of travelers for years to come.

The 700-foot-long tunnel under construction beneath Hartsfield-Jackson is for an extension of the Plane Train track that will enable the airport to add more trains transporting passengers between the terminals and concourses.

It’s a massively complex $331 million project that has been planned for more than five years and is expected to be finished in May 2024.

After the tunnel is completed, the airport plans to increase the number of Plane Trains in its fleet from 11 to 14. Airport officials say that will boost capacity 20% to 12,000 passengers per hour.

For passengers, that means Plane Trains will arrive faster — every 90 seconds instead of every 108 seconds today.

“Part of us being busiest is being extremely efficient,” Tom Nissalke, assistant general manager of planning and development at Hartsfield-Jackson, said Thursday during a media tour of the site.

“This project’s all about increasing efficiency,” he said. “... The Plane Train is one of the most vital systems of the airport.”

June 9, 2022 Atlanta - A 700-foot-long tunnel under construction beneath Hartsfield-Jackson International on Thursday, June 9, 2022. Sixty feet below the busiest airport, construction crews from the Clark Construction-led joint venture of Clark/Atkinson/Technique have been excavating a 833-foot extension for the Plane Train tunnel.  (Hyosub Shin / Hyosub.Shin@ajc.com)

Credit: HYOSUB SHIN / AJC

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Credit: HYOSUB SHIN / AJC

The tunnel extension will add a “turn-back” area for trains that will allow the increase in capacity. Today, a train headed to the domestic baggage claim station at the end of the line must wait for another train to turn back and go towards Concourse T in the other direction, because there’s no separate area for trains to move to when another train is arriving.

But the tunnel extension will fix that lack of space, the airport says.

Hartsfield-Jackson handled more than 110 million passengers in 2019, before traffic declined more than 60% in 2020 due to the pandemic. Passenger counts are rebounding as travelers take to the skies again.

The price tag for the project has fluctuated over the years, after an earlier estimate of $307 million. The now $331 million cost includes the excavation and construction of the tunnel, the additional train cars, new elevators and a fourth escalator for passengers getting off the Plane Train at baggage claim.

Construction at Hartsfield-Jackson Atlanta International Airport in June 2022. Miguel Martinez / miguel.martinezjimenez@ajc.com

Credit: Miguel Martinez

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Credit: Miguel Martinez

Late night disruptions

The construction has caused some disruption for travelers on late-arriving flights over the last year, which will continue through completion. After around 10-11 p.m. each night, Plane Train passengers arriving in Atlanta must walk the last leg of the trip from Concourse T to baggage claim. Plane Train operations return to normal each morning, when construction shuts down for the night.

“We’re having to do this very stealthily,” said Gabrielle Ferro, project manager for Clark Construction.

The process to relocate an elevator also means there are fewer escalators for passengers arriving at baggage claim.

The disruptions give a hint at the flurry of activity going on just outside the terminal and beneath the airport.

June 9, 2022 Atlanta - Construction view from a cage that is being lifted by a crane to transport crew between the ground and the tunnel under construction beneath Hartsfield-Jackson International on Thursday, June 9, 2022. Sixty feet below the world's busiest airport, crews from the Clark Construction-led joint venture of Clark/Atkinson/Technique have been excavating a 833-foot extension for the Plane Train tunnel.  (Hyosub Shin / Hyosub.Shin@ajc.com)

Credit: HYOSUB SHIN / AJC

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Credit: HYOSUB SHIN / AJC

Work to dig a shaft down into the ground outside the west end of the domestic terminal began in 2020 by a joint venture of Clark Construction, Atkinson Construction and Forest Park-based Technique Concrete Construction. To excavate the tunnel, workers blasted 45,000 pounds of dynamite. Each blast allowed 5-7 feet of progress per night, with the tunnel excavation completed in January 2022.

Nissalke said during the digging, workers found concrete slabs from the old Interstate 85 that used to run through where the airport sits today, before it was moved to make way for the terminal, which opened in 1980.

Now, the construction team is waterproofing and sealing the walls and completing the floor of the tunnel, before the rest of the work to extend the track begins. Workers descend into the tunnel in a metal cage that is lifted by a crane and lowered into the shaft underground. Due to a high water table, water must be pumped out of the tunnel during construction.

June 9, 2022 Atlanta - A gigantic crane lifts a cage to transport crew between the ground and the tunnel under construction beneath Hartsfield-Jackson International on Thursday, June 9, 2022. Sixty feet below the busiest airport, crews from the Clark Construction-led joint venture of Clark/Atkinson/Technique have been excavating a 833-foot extension for the Plane Train tunnel.  (Hyosub Shin / Hyosub.Shin@ajc.com)

Credit: HYOSUB SHIN / AJC

icon to expand image

Credit: HYOSUB SHIN / AJC

The project is also complicated by the fact that the tunnel is being built beneath the Sky Train to the airport’s rental car facility and MARTA foundations.

“We knew the job would be tough when we went into it,” said Billy Freeman Jr., CEO of Technique Construction. “It’s tremendous pressure.”


Hartsfield-Jackson’s Plane Train tunnel extension

July 2019: Construction at West curb begins.

May 2020: Shaft work begins.

October 2020: Shaft excavation completed. Horizonal tunnel work begins.

January 2022: Horizontal tunnel excavation completed.

June 2023: Horizonal tunnel work completion.

May 2024: Substantial project completion.

Tunnel extension by the numbers

700 feet long

60 feet deep

850 workers

Source: Hartsfield-Jackson

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