New Long Island Rail Road President Helena Williams confirmed critics' complaints Thursday about poor diesel train service.

Williams met with members of the Metropolitan Transportation Authority's unpaid commuter council, who criticized the frequent breakdowns that have lasted hours on some occasions.

"They are achieving less than 10,000 miles between failures," Williams said. "That's exceptionally low and that does nothing to help our service reliability."

Peter Haynes of the LIRR Commuters Campaign said the double-decker diesel trains, which are made by Kawasaki and powered by a General Motors locomotive, aren't dependable. The diesels are breaking down twice as often as electric trains, critics said.

"They were designed, tested and put into service by the LIRR," Haynes said. He said the diesel trains were "built to their specification and they're not even lasting 10 years, whereas the previous generation of equipment lasted 30 or 40 years."

Critics said repairs for the diesel trains, which are no longer under warranty, could cost the LIRR millions of dollars.

Williams said she's conducting an assessment of service reliability.