The second and final phase of the Portal North Bridge cutover is now underway, marking a critical stretch in the effort to replace the 116-year-old Portal Swing Bridge over the Hackensack River.

NJ Transit crews are moving the final track, along with overhead wires and other electrical components, from the aging bridge to the new Portal North Bridge.

NJ Transit President and CEO Kris Kolluri acknowledged the next five weeks could be difficult for riders.

"I know this next five weeks will be challenging and at times, frustrating," Kolluri said.

Officials say about 200,000 people travel from New Jersey into New York each day, and many commuters will need to rely on buses, ferries or PATH service while the work is completed.

Kolluri said weather remains one of the biggest concerns but noted that crews learned from the first cutover and already have needed supplies on site.

"The red flags I always look for is always the uncontrollables -- weather or anything else that is outside of our control," Kolluri said.

Despite the short-term inconvenience, officials say the project is designed to eliminate recurring problems caused by the aging bridge.

"We're replacing this 116-year-old bridge so it never becomes a problem for their commute again," Kolluri said.

The project is expected to be completed by Nov. 15.