Metro-North Railroad President Joseph Giulietti is retiring this summer, transit sources tell News 4 New York.
Giulietti took over Metro-North in 2014 after a series of derailments, including one that killed four people, and is credited with stabilizing the shaky commuter rail service. Howard Permut led Metro-North from 2008 until he stepped down in 2014.
It's not yet known who will replace Giulietti at Metro-North.
Transit sources say Giulietti's decision is a big loss because he's one of the most relied upon executives at the MTA.
The transit agency is facing renewed pressure to update its aging subway infrastructure amid persistent delays. And Long Island Rail Road commuters face what Gov. Cuomo called a "summer of hell" as tracks beneath Penn Station get a months-long overhaul from July to August.
Metro-North riders have fared better by comparison, though a train derailed last month, injuring 13.