https://www.hsrail.org/blog/northeast-corridor-choke-point-un-clogged/?emci=eea9083d-8624-f111-9a48-000d3a14b640&emdi=358b3e45-9f24-f111-9a48-000d3a14b640&ceid=3511506
Many more improvements in the works at various stages for this major rail corridor Philadelphia to NYC used by both Amtrak Accela and NJ Transit.