PATH (i.e., its parent the Port Authority of New York and New Jersey) is upgrading its signals. Great news. New York City depends acutely on its rail transit links, both within the City and between the City and its suburban communities. The tracks can carry a lot more traffic and they will have to if fewer people are to bring their cars into Manhattan.
Better signals make possible more efficient travel - reducing headway times safely and making better use of NYC's enormous investment in the rail tunnels. NYC's subway system needs the same makeover.