A Metro train passes track that is shut down for repairs after buckling in the heat on July 22 near the Ballston station. (Katherine Frey/The Washington Post)

Federal officials on Wednesday admonished Metro for the manner in which it stores and secures trains in rail yards, saying the agency’s employees have “universal misunderstandings” on how rail cars should be stowed — oversights that potentially put employees and passengers at risk.

Among the findings from federal inspectors: Metro supervisors routinely discourage the use of hand brakes and other required safeguards in rail yards because they are time-consuming and cumbersome for employees tasked with moving trains around.

In a 22-page report released Wednesday, the Federal Transit Administration issued a series of urgent safety steps Metro must take to address the chronic problems. The order requires Metro to propose and establish a new approach to safely storing cars, to train employees on the requirements and to ensure they have a proper understanding of the safety risks posed by rolling and unoccupied trains.

“Failure to properly secure unattended trains presents a significant safety risk across the rail transit industry,” the FTA said in the report, the third and final in a series of federal reviews into Metro safety procedures released this summer. “Unsecured and unattended trains or equipment can move in rail yards and on the mainline track, creating the potential for collisions with other trains, equipment, passengers or workers.”

Metro has 30 days to respond to the report and 60 days to establish a corrective action plan.

Metro board members and regional officials said they were concerned — but perhaps not particularly surprised — by the FTA findings. The observations from inspectors, they said, are emblematic of many of the problems facing Metro, including unclear protocol, lax adherence to safety procedures and we’ve-always-done-it-this-way attitudes.

“It’s another item on the laundry list of things we have to do,” said Jack Evans, chairman of the Metro board. “There can be no shortcuts. There can be no safety violations. People need to follow procedures.”

Rep. Gerald E. Connolly (D-Va.) called the new safety directive “another troubling breakdown of Metro safety culture.” Michael Goldman, a board member representing Maryland, said that although unsecured trains in rail yards are a serious issue, it pales in comparison with the other safety violations pinpointed by the FTA in recent weeks.

“I find that the other two issues are much more serious and raise more concerns with me,” Goldman said.

Goldman was referring to the other two FTA reports, the first delivering a scathing critique of the agency’s track maintenance program and the second addressing chronic problems with red-signal violations.

The final, four-month investigation, which resulted in six findings and corrective actions, was spurred by a series of alarming incidents involving rolling trains, including one collision. None of the incidents, which occurred in 2014 and 2015, resulted in injury, but a collision in January 2015 led to minor damage when an uncoupled maintenance car hit a motor vehicle parked across from the storage track at the Shady Grove rail yard.

In an incident in December, a two-car train rolled away in the New Carrollton yard, stopping only when an operator aboard applied the hand brake.

“Preventing unintended movement of rail vehicles is fundamental to safety and [the Washington Metropolitan Area Transit Authority] needs to do more to eliminate these types of incidents from happening,” U.S. Transportation Secretary Anthony Foxx said in a statement. “Verifying that a train has been properly secured is a common sense solution to prevent accidents.”

The report raised a litany of concerns. It said Metro does not provide sufficient safeguards when storing rail cars overnight, does not engage hand brakes and “wheel chocks” meant to prevent unoccupied trains from moving, does not provide clear and concise rules on storing trains, does not maintain its safety manuals to reflect its rules and procedures, and fails to ensure that its employees have a proper grasp on the rules. The FTA also noted that Metro has not ensured that its manuals are updated to reflect its 7000-series rail cars, the newest in its fleet.

According to the FTA, as Metro continued to expand and add new rail cars to its fleet in the late-1970s and ’80s, a culture developed: Maintenance needs required train cars to constantly be shifted and moved around. To speed up the process, the agency stored rail cars overnight without setting and releasing the hand brakes.

The pattern persists today. The FTA said that “due to challenges in applying handbrakes, the length of time required to apply them, and the difficulty in confirming their disengagement prior to moving trains under power, supervisors in rail transportation and car maintenance generally discourage use of these safety devices.”

Further, cars stored for more than 15 days often were not secured with wheel chocks or marked with blue flags, as required by Metro’s operating rules.

Metro said it would abide by the requirements outlined by the FTA.

“Metro has been working with FTA to address the issues identified in the Safety Directive and will undertake the necessary corrective actions within FTA’s deadlines,” Metro spokesman Richard L. Jordan said in a statement.

Federal safety officials have long warned of the hazards of not properly securing rail cars when they are not being used.

In 2013, a set of empty Chicago Transit Authority rail cars that had been set aside for maintenance came loose and traveled nearly a mile before colliding with a train full of passengers. More than 30 people were injured in the incident, which caused more than $6 million in damage.

The calamity led the National Transportation Safety Board to issue an urgent safety recommendation to the FTA, saying that rail transit systems needed to review their procedures for preventing stored, unoccupied rail cars from unintentionally moving. At the time of the incident, the CTA had no formal procedures in place for securing unattended equipment.

The FTA issued a safety advisory that instructed all transit agencies to review their procedures to prevent trains from moving when they are not supposed to. It is not clear whether Metro officials undertook such a review. In this latest investigation, FTA officials noted that Metro has procedures in place for securing empty rail cars but does not always follow them.

Lori Aratani contributed to this report.