Rehabilitation option for Hudson rail links 03 Dec 2020

Online rehabilitation of the existing twin rail tunnels under the Hudson River in New York, bringing Amtrak and local train services into Pennsylvania Station in Manhattan, is an option that has introduced a rethink of the current planning of the Gateway project. The objective of the project is to both increase rail capacity into Penn Station and to carry out needed upgrade and renovation of the existing twin tunnel infrastructure.

Fig 1. Route of the existing and new Hudson River rail underpasses

The project has been in development for several years and has been based on excavating and build and have in service the first of two new under river rail tunnels for the first of the existing 110-year-old tunnels to be taken fully out of service for a refit of mechanical and electrical systems and to undertake renovation of its internal structures. The operation would be repeated for the second of the existing running tunnels, once the first renovated tunnel is back in service, to maintain the minimum twin track facility, and as the second new drive under the river is progressing.

The new conceptual study, commissioned by the Gateway Program Development Corporation (GDC) and carried out by London Bridge Associates of the UK, proposes that rehabilitation of the old tunnels be undertaken inline, during night and weekend engineering hours when normal train services are suspended. This would allow rehabilitation of the tunnels without delay and save money in the full Gateway project program.

The old tunnels are not in fear of failure themselves, they are built in the hard Manhattan Schist of the region. Upgrade and replacement of outdated operating systems and reconstruction of deteriorating concrete linings and structures is required, both of which also suffered severe damage when the existing tunnels were flooded as a result of superstorm Sandy that hit the New York/New Jersey region in 2014.

Existing rail tunnels in need of extensive rehabilitation

The Gateway Program is considered the most urgent infrastructure program in the USA with a comprehensive rail investment needed to improve commuter and intercity services, add needed resiliency and create new capacity for the busiest section of the northeast rail corridor. The corridor is the most heavily used passenger rail line in the country hosting more than 2,200 train movements and 800,000 passenger trips daily. More than 150,000 commuters/week were carried by Hudson River train services in pre-Covid times. GDC is a New Jersey not-for-profit entity with Board members representing Amtrak, the national passenger train operator across the USA which owns the existing Hudson River tunnels, and the States of New York and New Jersey that govern and fund rail service agencies including New Jersey and New York Transit organisations. GDC was incorporated in 2016 to oversee and effectuate the Gateway Program in coordination with Federal and local partner agencies. Construction of the full project is currently estimated at $11.4 billion with funding being requested from the Federal and State Governments and local sources.

Analysis of the study by London Bridge Associates (LBA) confirms that all elements of the rehabilitation scope included in the Hudson Tunnel Project are required to comprehensively rehabilitate the tunnels. These include reconfiguring and rebuilding the concrete bench walls; replacing high-voltage electrical cables and other cables currently inside the bench walls; a 360 degree repair of the concrete lining, including areas behind the bench walls and beneath the ballasted track bed; replacing the outdated ballast and wood tie track-bed with a direct-fixation concrete system; and upgrading and replacing the catenary overhead system and dated cables and signals with state-of-the-art equipment. The report acknowledges that existing levels of Northeast Corridor train services must be maintained throughout the construction period.

Inline rehabilitation of old rail tunnels is an operation that is well established and used for rehabilitation of several aging rail tunnel infrastructure, particularly in Europe and elsewhere in the world. With investigation and knowledge of these experiences in hand, the LBA report recommends a conceptual approach to repairing the tunnel lining and sealing leaks first, and considers alternatives to the existing concrete bench walls for protecting cables, such as combinations of racking, troughs, and metal strongboxes that have been used successfully elsewhere. The LBA approach prioritizes the root causes of unreliability evidenced by train delay data attributed to track conditions, overhead power, and signal problems and recommends accelerating work to correct these issues as quickly as possible.

Portal of existing Hudson rail link in New Jersey

LBA noted, based on other tunnel rehabilitation works around the world, that rehabilitation of the Hudson tunnels could be expedited and possibly carried out during in service maintenance windows on nights and weekends, and that the concept warranted further study by the Gateway partners. It confirms that further design and contractor outreach would be required to determine, develop, test and practice the means and methods that would allow continuation of the current levels of service. The analysis recommends proceeding with rehabilitation while continuing ongoing state of good repair work on the infrastructure and assumes between 85% and 100% of regular weeknight and weekend maintenance windows when tracks are out of service, being used for the repair work to progress. It also assumes that further study by the railroad operators will determine feasibility of the option.

The report has been received with a mixed reception. Governor of New York State Andrew Cuomo has received the report positively saying: “We have a report that says the tunnels can be rehabilitated. There is also a desire by Amtrak and many people to build new tunnels, which I think is a good idea. One is not the enemy of the other.” New Jersey Governor Philip Murphy is less enthusiastic, saying the proposal would make commuters “more miserable,” because it would require night-time and weekend service reductions. “We need four tunnels under the Hudson and we need to do it in a way that does not disadvantage and further impact the lives and the experience of the commuters from New Jersey,” he said.

Steven Cohen, New York Trustee and Chair of GDC, said, “We are all saying the same thing: we need the new tunnels to add access, but that is a decade away and we do not want the current systems in the existing tunnels to fail in the meantime. So it is worth looking at whether we can rehabilitate the old tunnels while we build the new ones.”

Alignment of the new tunnels being built as part of the Hudson Yards redevelopment project in Manhattan

Tony Coscia, Amtrak Trustee and Vice Chair of GDC, said, “Construction of a new Hudson River Tunnel is the fundamental reason GDC was created and is our top priority. As we await Federal environmental approval to begin construction, a full review of the very best means, methods and practices to preserve the existing tunnels is an important part of stewardship of Amtrak of this critical infrastructure. The concepts suggested by LBA are being evaluated to determine feasibility, cost, and schedule impacts, so that we can determine the best ways forward.”

Jerry Zaro, New Jersey Trustee and GDC Treasurer, said, “The project needs to do two things, construct a new two-track tunnel and rehabilitate the existing tubes to serve for the next hundred years, and to do so as soon as possible. In that spirit, we welcome the advice and suggestions contained in the LBA report, but we will take no action recommended by the report unless and until we are 100% certain we can reliably do so and bring back uninterrupted service the following morning."

Increasing rail capacity under the Hudson into Penn Station and rehabilitation of the existing tunnels was a project known as Access to the Regions Core in the 2000s. Contracts were awarded for start of the new tunnel excavations and had mobilized before then Governor of New Jersey Chris Christie withdrew the New Jersey State funding contribution and caused cancellation of the project.

Amtrak then picked up the project, knowing the urgent need for the two parts of the project, and began its promotion as the new Gateway project in 2011. The alignment of the new rail infrastructure into Penn Station has been reserved and is being constructed as part of a major urban redevelopment of the Hudson rail yards on the east side of Manhattan. A major cost reduction exercise for the project in September 2019 reduced the budget of the new under river tunnel works to US$9.5 billion from previous estimates of US$11.1 billion.