WASHINGTON, June 12 (Reuters) - This week's reopening of Baltimore's main shipping channel - less than three months after the Key Bridge collapse - was due to expertise gained from a COVID-era task force, a highway overpass collapse and the 2021 infrastructure law, government officials said.

The deadly March 26 collision of the cargo ship Dali into the Francis Scott Key Bridge had paralyzed a major transportation artery for the U.S. Northeast.

Within hours, President Joe Biden directed aides to get the channel reopened, the bridge rebuilt and vowed the federal government would cover the full costs. His administration has previously faced criticism for its initial response to the 2023 derailment of a train in Ohio.

Federal officials said on Monday that full access to the channel had been restored after the removal of 50,000 tons of debris. On Wednesday, Maryland Gov. Wes Moore and other officials are holding a press event to mark its reopening.

After the collapse, the Coast Guard quickly established a Unified Command to coordinate search, recovery and response efforts. It oversaw more than 1,500 individual responders that involved 56 federal, state, and local agencies along with 500 specialists operating a fleet of boats to remove steel and concrete debris and address shipping impacts.

"I think that one of the most important things we did was establishing the unified command," White House deputy chief of staff Natalie Quillian told Reuters.

"So there was clear command and control of what is a very complex operational challenge across stakeholders from federal and state government and the private sector."

For example, the U.S. Army Corps of Engineers (USACE), which oversees the federal navigation channel, was able to tap the U.S. Navy Supervisor of Salvage for the massive operation.

"That's exactly the power of the unified command," said Col. Estee Pinchasin, Baltimore district commander for USACE, which by early April had set an ambitious timetable for reopening the channel.

A council created by Biden in 2021 to address COVID-related supply chain shortages was convened shortly after the bridge collapse and federal agencies opened specialized offices to monitor supply chain issues.

"We developed these protocols during the first year of the pandemic," White House National Economic Council director Lael Brainard said. "This very intensive sprint that we immediately activate to basically troubleshoot and share information."

Brainard also cited lessons learned from the June 2023 collapse of an Interstate-95 overpass in Philadelphia that was quickly reopened.

"The I-95 collapse was such a rapid response that we had a sense of, 'OK we know what to do," he said.

Brainard and Transportation Secretary Pete Buttigieg led a call to ensure business, labor and port operators had the "same information to help them rapidly develop workaround plans."

Both cited the $1 trillion infrastructure law that has dramatically boosted spending on bridges and other projects as having given the administration know-how and "muscle memory" to tackle big challenges.

Buttigieg's office approved $60 million in emergency funds for Maryland to rebuild and remove debris, while the U.S. Army Corps and Coast Guard said on Tuesday they have spent nearly $100 million on the bridge response and debris removal.

Buttigieg also repurposed a grant so more cargo area could be established and waived hours of service limits for impacted trucking.

"When the president of the United States says that every part of this administration should do everything you can think of within the limits of law - we can actually move quite quickly," Buttigieg told Reuters.

A replacement bridge will cost an estimated $1.7 billion-$1.9 billion and federal officials are working to speed environmental approvals. Maryland hopes it will be completed by late 2028.

(Reporting by David Shepardson; Editing by Edwina Gibbs)