A “major direct federal investment” of $50 billion is needed to save crumbling U.S. rail infrastructure, according to Sens. Chuck Schumer and Kirsten Gillibrand.

Amid increasingly frequent service interruptions at Penn Station, the New York lawmakers penned a letter dated Friday to U.S. Transportation Secretary Elaine Chao, calling for the federal money to help alleviate “maddening” train cancellations at Penn, the nation’s busiest rail hub.

“The Long Island Rail Road is the only mass transit option for the hundreds of thousands of Long Island commuters who travel to and from the city each day, and they deserve better than the maddening delays and cancellations that continue to occur almost weekly,” the senators said in a joint statement. “For too long, the feds have underinvested in rail and transit systems, including the LIRR-connected Amtrak Northeast Corridor, and left us where we are today.”

The cost of the Northeast Corridor’s backlog on repair work alone has tipped to $38 billion, according to the two lawmakers.

That backlog is evident at Penn Station, owned and operated by Amtrak, where decaying rail infrastructure is causing headaches for commuters. Nearly 80 trains were canceled during the evening rush-hour commute Wednesday, stranding tens of thousands of passengers at Penn. As the federal government develops its budget for the 2018 fiscal year, Schumer, the Senate minority leader, and Gillibrand in their letter advised Chao to consider the Senate Democratic Caucus’ blueprint released in January, which outlines $50 billion in federal dollars to modernize the country’s rail infrastructure.

“Addressing the critical maintenance need at New York’s Penn Station and the entire Northeast Corridor must be a priority for the administration, and we stand ready to work with you on that effort,” Schumer and Gillibrand said in their letter, written before a summer of planned delays at the Manhattan hub.

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The LIRR faces a 25 percent service reduction in coming months as Amtrak repairs tracks at Penn Station. While the work would have a “significant impact” on commuters, it would also eliminate the possibility of track-caused disruptions “for a good, long time,” according to Charles “Wick” Moorman, president of Amtrak, who testified at a specially convened New York State Assembly session last week in Manhattan.

The U.S. Department of Transportation did not immediately respond to requests for comment.