As Amtrak continues to set ridership records, chief executive Joseph Boardman said Wednesday that new rail tunnels to New York are "critical" to meeting growing passenger demand.

Amtrak is seeking $35 million this year to advance plans for its $13.5 billion Gateway proposal to increase rail service on the Northeast corridor by adding two tunnels under the Hudson, replacing the century-old Portal Bridge near Newark, and expanding Pennsylvania Station in New York.

The Gateway project, which Amtrak hopes to complete by 2025, is a key part of Amtrak's effort to increase capacity on the overloaded Northeast corridor.

And it is integral to the railroad's long-term goal to build a new high-speed Northeast corridor rail route that would allow trains to make the 426-mile trip between Boston and Washington in three hours and 23 minutes - compared with the current eight hours on Amtrak's Northeast Regional trains, or six hours and 37 minutes on Acela Express.

The Gateway project was unveiled early last year, about four months after Gov. Christie canceled another rail-tunnel project, the ARC (Access to the Region's Core) tunnel, citing its costs.

On Tuesday, the Government Accountability Office released a report with lower cost estimates and a smaller financial share for New Jersey than those cited by Christie when he killed the ARC tunnel.

Boardman said Wednesday that the GAO report, which said the existing 100-year-old Hudson River rail tunnels "cannot meet the access and mobility demands of the future," buttressed the case for Amtrak's Gateway project.

"If we don't get our infrastructure improved, we're going to have problems growing anything in the Northeast," Boardman said in an interview. "We're out of space - in the tunnels, on the tracks, in Penn Station."

"There has to be a change in the attitude and discussion about transportation in this country" and the role of railroads.

Funding for the Gateway project, and for Amtrak, remains uncertain, with Congress sharply divided over continuing subsidies for the national rail agency.

Boardman cited Amtrak's growing ridership - up 44 percent since 2000 - as evidence of its value.

New ridership numbers released Wednesday showed that Amtrak passenger traffic was up 3.7 percent in the first six months of the fiscal year (October through March).

Amtrak has set ridership records in eight of the last nine years, including last year, when it carried 30.2 million passengers.

The most recent numbers show ridership was up 5.2 percent on the Northeast corridor, including an 8.2 increase on Northeast Regional trains and a 1.3 percent decline on Acela Express, the fastest and most expensive of Amtrak's trains.

Boardman said the decline in Acela ridership may have been caused by the mild winter in the Northeast, which allowed some weather-wary travelers to return to autos and planes. He also noted that improved Internet service on the cheaper Northeast Regional trains was now better than on Acela trains, which may have lured some riders away from Acela.

Ridership on the Philadelphia-to-Harrisburg "Keystone" route was up 4 percent for the six-month period.

Is America ready for high-speed rail? A four-part Inquirer series looked at the issues. Go to