MENDHAM, N.J. - Former NJ Transit executive director George D. Warrington, who led one of the nation's busiest rail and bus systems for almost five years, has died. He was 55.

Warrington, who left office in March, died Monday at his Mendham home after an eight-month battle with pancreatic cancer, NJ Transit spokeswoman Penny Bassett Hackett said.

Warrington was president of Amtrak, the national commuter rail system, when he was chosen to take charge of NJ Transit in March 2002 by then-Gov. James E. McGreevey. During his tenure, the system added 100 trains to the schedule and increased or extended trips on more than 50 bus routes.

Warrington also won praise for helping to create thousands of commuter parking spaces around the state and improving its budgeting process. He also improved the rail system's on-time performance and oversaw last year's debut of the agency's multilevel trains, which feature wider aisles, more leg room and added seating.

He also was a strong proponent of plans to build a commuter train tunnel under the Hudson River. If approved, the proposed $7.5 billion tunnel linking New Jersey and New York would double commuter rail capacity between the two states.