Democratic former Vice President Joe Biden took a jab at Republican New Jersey Gov. Chris Christie over the region's mass transit woes Friday, chiding Christie's "infinite wisdom" in killing a rail tunnel project several years ago.

Biden, who speaks often of his love of commuting by rail, told an urban planning conference in New York that commuters in the region are still in "purgatory."

New York's Penn Station has been the site of two recent derailments and other delays due to disabled trains, hampering travel on the Northeast Corridor.

A Christie spokesman reiterated comments the governor made Thursday that the tunnel wouldn't have been near completion anyway and that it was a bad deal for New Jersey because New York wasn't contributing funding to it.

He also contended New Jersey taxpayers would have been required to cover as much as $5 billion in cost overruns.

"There is a lot of historical revisionism going on here," spokesman Brian Murray said.

The existing 110-year-old tunnel connecting New Jersey and New York operates at capacity during peak hours and is a source of regular delays due to overhead wire problems and other issues.

Christie is a supporter of the $20 billion-plus Gateway project, which would build a new tunnel, expand Penn Station and make other rail improvements.

On Friday, Biden called Gateway the most important infrastructure project in America. More than 200,000 rail commuters pass through Penn Station each weekday, and delays at the station can ripple along Amtrak's line between Boston and Washington, D.C.