Sen. Charles Schumer is calling out Amtrak and the MTA for sitting on $432 million in federal funding he helped secure for critical repairs inside the superstorm Sandy-damaged East River Tunnels leading into and out of Penn Station.

In a letter sent Thursday to acting Metropolitan Transportation Authority Director Veronique Hakim and Amtrak President Charles “Wick” Moorman, Schumer said both rail agencies have made “no meaningful progress” in a planned effort to rehabilitate a pair of tunnels that were inundated with millions of gallons of corrosive saltwater in the October 2012 tempest.

“I am acutely concerned about the speedy and effective use of these funds by the MTA and Amtrak, and specifically ask your agencies to articulate a clear plan to make these vital repairs,” Schumer wrote. “We have seen — and hundreds of thousands of Long Island commuters have directly experienced — what can happen when the transit agencies in charge of this infrastructure do not stay on top of needed repairs, and we cannot let a similar situation develop with regard to the East River Tunnels.”

In a statement, Amtrak officials said they “completely agree with Senator Schumer’s call to urgently advance” the tunnel rehabilitation work.

“Amtrak is already progressing the design work for this multiyear project and are anxious to work with the MTA to solidify the funding and overall plan for these essential repairs,” spokeswoman Christina Leeds said.

The MTA did not respond to requests for comment.

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The letter comes as commuters await details on a separate plan by Amtrak to replace aging track infrastructure at Penn Station, where several recent service disruptions have originated. Details of the project, which is expected to significantly impact Long Island Rail Road service this summer, are expected next week.

That work will not include the plan to repair the tunnels, which Amtrak proposed in 2014 but had trouble funding. In June, the Federal Transit Administration awarded $432 million in Sandy repair grants to the MTA. Schumer said in the letter that the award came at his “urging,” and with the understanding that the MTA would give the money to Amtrak, which was not eligible for FTA grant funding, to do the work in the tunnels, which are primarily used by the LIRR.

Meanwhile, MTA commuter frustration was the source of the latest dust-up between New York Mayor Bill de Blasio and Gov. Andrew M. Cuomo. During a radio appearance, de Blasio chided Cuomo for not accepting responsibility for rising subway delays.

“He’s in charge and he should just own up to it and take this responsibility seriously and put forward a plan,” de Blasio said.

Cuomo spokeswoman Dani Lever responded by pointing out that the governor only appoints six of the MTA Board’s 14 members, and accusing de Blasio of not paying the city’s fair share of the MTA’s capital costs.

“If the mayor wants to help, let him fully fund his obligation,” Lever said.