Not possible without double tracking, or seriously reducing rush hour service. Making train 49's deadhead return into a revenue run would close that gap a little.
Weekend Path service to both lower and midtown Manhattan, and running all Port Jervis trains express are the low hanging fruit for improving off peak utilization of the line. Peak hour ridership is pretty good (shown by the utilization of 7 car trains), and the only thing that's going to help that grow more is when Gateway is finally built and trains can run directly to NYC. The addition of Secaucus already cut 15 minutes out of the trip from any Port Jervis Line station to midtown (vs staying on the train to Hoboken and going through all the Path stops to 33rd), and I'd think a one seat ride would be able to cut another 5-10 minutes out of the trip with the Secaucus transfer. It takes 15 minutes to get from SEC to NYP on a NEC train, but you also need 5-10 minutes to do the transfer, which the one seat ride eliminates.
Weekend Path service to both lower and midtown Manhattan, and running all Port Jervis trains express are the low hanging fruit for improving off peak utilization of the line. Peak hour ridership is pretty good (shown by the utilization of 7 car trains), and the only thing that's going to help that grow more is when Gateway is finally built and trains can run directly to NYC. The addition of Secaucus already cut 15 minutes out of the trip from any Port Jervis Line station to midtown (vs staying on the train to Hoboken and going through all the Path stops to 33rd), and I'd think a one seat ride would be able to cut another 5-10 minutes out of the trip with the Secaucus transfer. It takes 15 minutes to get from SEC to NYP on a NEC train, but you also need 5-10 minutes to do the transfer, which the one seat ride eliminates.