President Trump waves as he walks across the South Lawn to board Marine One on Tuesday. (Andrew Harnik/AP)

President Trump signed a resolution Tuesday giving final approval to the long-awaited Metro Safety Commission, the last legislative step in the years-long effort to establish an oversight organization tasked with making Metro safer.

But there’s plenty more that must still happen before the new agency is up and running.

Federal regulators, members of Congress and local officials have long demanded a new agency to help fix Metro’s safety problems and prevent accidents such as the 2009 Red Line crash at Fort Totten and the 2015 L’Enfant Plaza smoke incident that resulted in deaths and injuries. Nearly two years ago, the Federal Transit Administration took on temporary responsibility for safety oversight at Metro, an emergency measure put in place by then-Transportation Secretary Anthony Foxx.

Since that time, Foxx and his successor, Elaine Chao, have urged regional officials to establish a permanent safety organization that will meet federal standards and take the responsibility out of the hands of the FTA.

The process of getting that body in place has taken much longer than many expected. The D.C. Council approved the required legislation last year, and the Maryland and Virginia legislatures passed bills earlier this year. The legislation ping-ponged around Congress for months before it received final approval 2½ weeks ago.

And with little fanfare, Trump signed the resolution Tuesday, turning it into law.

But it will still be a while before the safety organization exists — the District, Maryland and Virginia are still looking for office space for the newly minted agency, they will need to find employees to staff that office, and they are seeking out at least six people with extensive rail and transit safety experience who can serve as commissioners. (Each jurisdiction is required to have two commissioners, along with an alternate.)

Once everyone is in place, the safety organization will have to go through a formal handoff process with the FTA, which will require documentation, vetting and in-person assessments.

The jurisdictions are hustling to complete this certification process by the end of this year. And they’re operating in the context of an increasingly urgent ticking clock: Since February, the federal government has been withholding millions of dollars in federal funds from transit agencies around D.C., Maryland and Virginia.

Despite complaints from Congress, there is no indication that Chao has altered her vow to withhold that money until the Metro Safety Commission is federally certified and in full operation.

With Trump’s signature, the nascent oversight agency is a legal reality — but it’s still not the kind of brick-and-mortar organization that will help the jurisdictions get their transit funding back.