Amtrak, which owns the rails, is replacing rail ties. Track 4 will be taken out of service for several months between New Brunswick and Metuchen.
NJ Transit's new schedule reflects keeping one track in each direction for local service while using the remaining track for express trains during peak hours.
The new schedule shows slightly longer trip times for trains to and from Trenton. There are changes to departure times and a reduction in the total number of train stops through the work zone during non-peak hours.
Amtrak is installing special boarding platform bridges at New Brunswick, Edison and Metuchen stations.