Decades of mismanagement led to a workplace culture where, incredibly, more than 90 percent of 1,600 subway-signal repairmen routinely filed fake inspection reports, the MTA’s subway and bus chief admitted yesterday.

Calling the problem “exceptionally serious,” NYC Transit President Thomas Prendergast along with other subway brass endured a two-hour grilling by a City Council committee.

MTA inspector-general reports in 2000, 2005 and 2010 highlighted faked inspection reports and explained that faulty red/yellow/green signals — which tell train operators to halt or proceed — could put riders in danger.

But false reporting still exists — and Prendergast conceded it might involve more than 90 percent of the signal workers.

“It’s a failure of senior management. It’s not a failure of any employees,” Prendergast said after the hearing. “You’ve got a culture problem.”

Officials couldn’t identify any accidents over the last decade that resulted from the faked inspections — though it’s possible that subway delays have resulted from failures in the system’s 15,000 signals.

When something goes wrong with a subway signal, the system is designed to prevent accidents by automatically triggering train brakes, stopping them in their tracks.

Employees who blatantly falsify reports can be fired or disciplined, Prendergast said.

But if they falsified the reports under orders or with the knowledge of supervisors, punishment is less likely, he said.

And there’s a shortage of workers qualified to inspect and repair signals, Prendergast admitted.

About 1,600 NYC Transit workers now perform signal work — a number Prendergast called “a very small universe — exceptionally small.”

NYCT can’t afford to lose all the workers who filed false reports because “we would create a state or conditions that are far greater risk to the public,” Prendergast said.

Transport Workers Union Local 100 — which represents subway and bus workers — says employees are intimidated into submitting false signal-maintenance reports.

“The culture of the company for decades has been to force workers to sign off on an inspection if that inspection has not been performed,” said Local 100 President John Samuelsen, and “the MTA has forced signal maintainers to inappropriately sign off on forms.”

bill.sanderson@nypost.com

