What’s Involved in Upgrading a Century-old Subway Signal System?

Subway systems like PATH and the New York City Subway need ongoing maintenance to maintain service for the enable more frequent and reliable subway service. A multi-year effort is underway to overhaul the signal systems used on both systems, and since both operate 24/7, the work is often squeezed in during nights and weekends when passenger demand is lighter. In 2014 and 2015, PATH service between Exchange Place in Jersey City and the World Trade Center in Lower Manhattan was suspended on some weekends from 11PM Friday-5AM Monday, and in 2016 PATH service between Hoboken-33rd Street service was suspended for 17 weekends between August and December.

These service suspensions allow crews to install a brand new, federally mandated Positive Train Control (PTC) signal system that will increase safety and permit trains to run more frequently. They are also enabling repair of infrastructure in the tunnels damaged by Hurricane Sandy.

Diagram of PATH routes designed by Beyer Blinder Belle Architects

From the status report published by PATH:

Since February, approximately 280,000 square feet of metal tunnel surfaces and equipment were power washed of salt residue left by Superstorm Sandy floodwaters and corroded metal replaced – the entire area along the line impacted by salt. Additionally, significant progress occurred toward installing new computerized signals for increased operational safety with the placement of thousands of feet of new cables.

Sandy’s floodwaters left behind an insidious salt residue that rusts metal cables, equipment and the shell of the tunnel itself. The corrosive salt required a painstaking, labor-intensive cleaning process, beyond what occurred in the initial aftermath of the storm to return train service as quickly as possible.

The Port Authority – like other mass-transit systems around the nation – also is working to meet a federal mandate to install a Positive Train Control (PTC) system to help reduce human or mechanical errors and provide added safety on the rails. PTC is an enhanced signal technology that automatically applies a train’s brakes if an accident appears likely, potentially saving injuries and lives.

Floodwaters in Sandy’s aftermath destroyed much of the substantial prior work PATH had completed on the PTC system, requiring replacement of those components and significantly setting back the agency’s schedule and budget. The Federal Transit Administration helped the Port Authority recoup those financial losses.

The PTC improvements are part of an overall $580 million, comprehensive signals modernization program that ultimately will improve service for PATH riders by allowing trains to run more frequently while maintaining or improving safety.

The 2014 weekend closures allowed PATH to continue with the installation of cable, fiber, compressed air lines and conduit material for signal and communications equipment, which will help meet the PTC requirements. The work also included installation of communication antennas and signal junction boxes.

Since Sandy, infrastructure improvements have been vast, with a myriad of utilities in the tunnel replaced, including power and communications equipment, rail, third rail and track. Nearly two miles of corroded rail fasteners were replaced to better secure the track bed.

The Port Authority announced the service changes to give riders two months’ notice, a notable improvement over the announcement of 2014 closures, which was criticized for giving riders only about a week’s notice. The PATH Riders Council and PATH discussed the importance of a longer advance notice period for future service changes, and the earlier advance notice is a good outcome of that collaboration.

Newark-WTC service will continue to run on its usual schedule, providing 24/7 service between Newark and Manhattan. In addition, direct service between Hoboken and World Trade Center – normally available on weekdays between 5AM-11PM – was added on the weekends when 33rd Street service was suspended. The addition of weekend service will give Hoboken and Jersey City residents 24 hour access to Manhattan via Hoboken, Newport, and Exchange Place stations. Limited shuttle bus service will operate between WTC and West 29th Street along Sixth and Seventh Avenues during the weekend closures.

With the significant work completed on the Downtown Hudson Tubes in 2014, maintaining weekend service on the Newark-World Trade Center and Hoboken-World Trade Center lines while work is performed on the Journal Square-33rd Street via Hoboken line could provide service at most, if not all, New Jersey stations, as well as connections to 11 New York City Subway lines within two blocks of the World Trade Center station.

PATH officials estimate the new signal system will enable up to a 20% increase in service, which will help PATH accommodate growing demand. Although disruptions can be inconvenient, the work underway is essential to the performance, capacity, and resilience of the transit systems that power the NY/NJ urban economy.

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