Metro has replaced about 380 brake parts on multiple types of rail cars after similar pieces fell off two rail cars in recent weeks, according to the transit agency. But the reason why the “friction rings” fell off two rail cars with riders aboard remains under investigation. And officials have no estimates of how much the precautionary replacements are costing the agency. Metro spokesman Dan Stessel said crews also are reinspecting rail cars more frequently to continue the search for problem parts. The agency says it exceeding the standards of the manufacturer, replacing them before they are due. –Kyta Weir
