The part I am referring to is on the jointly owned PRR/NH line to Hells Gate.
From Pennsylvania Station to Harold interlocking the line was originally Pennsylvania Railroad (PRR). It had PRR-style signals.
From Harold interlocking to S.S. 4, Oak Point (technically to S.S. 3, Bungay), the line was New York Connecting Railroad, which was jointly-owned by both the PRR and the New Haven Railroad (NH), but was operated and maintained strictly by the NH and had NH-style semaphore signals. This line included Hell Gate Bridge.
From S.S. 4, Oak Point, to S.S. 22, New Rochelle Junction, the line was the Harlem River Branch of the NH and had NH-style semaphore signals.
Not counting the phase break indicators at (formerly S.S. 8) West Farms Junction, any PRR-style signals installed would have been Penn Central or Amtrak, thus making them relatively recent (i.e., less than 40 years old) applications.