Federal transportation officials ordered the Metro-North Railroad on Friday to quickly overhaul its signal system and temporarily put an extra worker in the driver's cab on some routes that have major speed changes, including the one where a commuter train derailed Sunday, killing four people.

The train flew off the tracks in the Bronx after hitting a curve at 82 m.p.h. where the speed limit was 30 m.p.h. The operator told investigators he nodded at the controls and applied the brakes too late.

The railroad has until Dec. 31 to provide a plan and target dates for modifying the signal system.

Meanwhile, funeral services were held Friday for two victims of Sunday's derailment, Jim Lovell, a sound and lighting technician, and Donna Smith, a paralegal. - AP