For the second time in less than a month, a part of a rail car brake assembly has fallen from a Metro train, according to transit officials.

The latest incident occurred Friday afternoon when a “friction ring,” a part Metro officials have likened to a vehicle brake disc, fell from an Orange Line train headed toward New Carrollton shortly before noon Friday. The train became disabled near Stadium-Armory station. No one was injured and passengers were transferred to other trains, Metro said. However, service was affected for more than two hours.

Metro said it will inspect 464 rail cars that have similar brakes, the 2000, 3000 and 4000 series rail cars. The authority has 1,142 rail cars in its fleet, which have been delivered in batches designated with a series number over the last 36 years. Transit officials said the inspections will last into early next week.

On Dec. 20 a friction ring fell from a 5000 series rail car, damaged two more rail cars and shut down service along the downtown core of the Orange and Blue lines for hours. Metro inspected the brakes on all of its 5000 series rail cars and pulled 16 from service to be examined for possible “hub failure.” Officials are awaiting results of metallurgical tests in that incident. Metro said the brake assembly in the Friday incident is of a different design and is made by a different company.