Gall Zeidler Consultants Marks 25 Years 

In 2025, Gall Zeidler Consultants will be celebrating its 25th year of providing engineering services to clients involved in underground and tunneling work. Founded in 2000 by Vojtech Gall and Kurt Zeidler, the firm has developed an impressive resume on projects across the United States and internationally, spanning transit, highway, water/wastewater and other works for owners, contractors and engineers. Some of these projects are among the largest undertakings in the country – and the world. 

Gall Zeidler Consultants’ expertise spans conventional and mechanical tunneling construction, from feasibility studies through to detailed design, working in a variety of roles including construction management and site support – and everything in-between. Since its founding, the company has expanded its range of services and expanded geographically with nine offices across four continents today.

Founding

Gall Zeidler Consultants was established at a time when Boston’s Big Dig and the Washington, D.C., Metro were among the most prominent underground works being built. Both of these projects required unique solutions to complex challenges in urban environments. It was about this time that the Sequential Excavation Method (SEM) of tunneling was more widely implemented in the United States, and both Gall and Zeidler had prior experience with the method dating back to academia.

Both Gall and Zeidler recognized the need to provide specialty services for complex underground projects at a time when a new wave of infrastructure construction was being conceived in the Northeast, particularly in New York City with megaprojects including East Side Access, the new trans-Hudson transit tunnel (now known as Gateway), and the Second Avenue Subway. They realized that they would be able to contribute to the U.S. market by joining forces, and Gall Zeidler Consultants was launched in 2000, now based in Ashburn, Virginia, near Washington, D.C. The proximity to Dulles International Airport allowed for an early involvement in the airport’s Automated People Mover system where GZ became an integral part of the larger program and construction management efforts.

“At the time we established Gall Zeidler Consultants in 2000, the D.C. Metro was still under construction, and we recognized that the tunneling market in New York City, which had been relatively slow for decades, was primed for growth,” Gall said. “We saw the opportunity to support this new development in the Northeast with state-of-the-art tunneling technology.”

While the company’s history is rooted in projects in the Northeast Corridor, it has expanded with the opening of offices in New York, San Francisco and Toronto in North America, as well as London, U.K.; Santiago, Chile; Salzburg, Austria; New Delhi, India; and Singapore. Since its founding, the company has been involved in projects totaling more than 450 miles of tunneling across the Americas, Europe, Asia, Australia and Africa.

The company’s range of services includes detailed design, program management, construction management, feasibility studies, geotechnical investigation, procurement and rehabilitation, among others. 

Since the beginning, the mission of Gall Zeidler Consultants has been to provide client-oriented services for owners and contractors that are implementing tunneling projects, offering economic and efficient state-of-the-practice solutions.

Starting Out

The new company got involved in one of the largest underground construction projects in the United States early in its existence in the form of the East Side Access (now known as Grand Central Madison) for the MTA’s Long Island Rail Road in New York. Gall Zeidler Consultants was involved from 2001-2023, advising on the design, ground improvement, instrumentation and monitoring programs, waterproofing and final lining alternatives, construction planning, and construction management and inspection services. 

Construction used two hard rock tunnel boring machines for running tunnels, roadheaders and drill and blast methods for the caverns, cross passages, shafts, and ventilation structures. East Side Access entailed excavating tunnels approximately 120 ft beneath Manhattan streets for a length of about 25,000 ft. One of the changes implemented by the GZ team was switching from the use of steel sets for passive support of the Manhattan schist to active support using rock dowels and bolts followed by thin layers of shotcrete to achieve a flexible structure for better load transfer. The initial liner was followed by a watertight membrane and a final liner.

It wasn’t long before Gall Zeidler Consultants participated in other notable New York City area projects. The company developed conceptual designs of construction methods for the No. 7 Line Extension, which involved construction of approximately 1.5 miles of twin TBM tunnels and two large-span station caverns 60 to 100 ft wide and 1,000 ft long. 

In 2007, Gall Zeidler Consultants was part of the design team for the Trans Hudson Express, which was eventually cancelled but has since been reborn as the Gateway Program. The most notable portion of that project is the construction of twin tunnels under the Hudson River to provide added capacity and redundancy for the 110-year-old plus North River Tunnels that carry Amtrak and New Jersey Transit trains along the Northeast Corridor.

In 2024, GZ, as part of the mPa Delivery Partner team (a Joint Venture comprised of Mace, Parsons, and Arcadis), was selected to act as the Delivery Partner (DP) for the Hudson Tunnel Program. The role of the Delivery Partner is to provide project-wide Project Management (PM) and Construction Management (CM) to the owner and its partner agencies. GZ is acting as tunnel experts for the Delivery Partner team and is providing staff that is working directly under the Gateway Development Commission itself, Amtrak, and the Port Authority of New York and New Jersey. In this role, GZ is providing Resident Engineering and CM services for contracts that are under construction, bid review and CM services for contracts that are in procurement, and technical review services for contracts that are still in design. GZ is providing project-wide PM services to the Gateway Development Commission that involves interface management, schedule tracking and review and providing contract packaging advice and oversight. Finally, GZ is supporting the digital transformation of the project and is advising and supporting the project’s BIM adoption.

Expanding Footprint

On the heels of its successful experiences in the Northeast, Gall Zeidler started working on the Pacific Coast, landing projects in the San Francisco Bay area and in Seattle for Sound Transit. GZ has participated in almost every major underground project for Sound Transit dating back to 2005 with work on Beacon Hill Station. Other projects for Sound Transit include Northgate Link, University Link, the Bellevue Tunnel on East Link Extension, and the upcoming Ballard Link Extension and West Seattle Link Extension. 

The first major project for Gall Zeidler in California was the Devil’s Slide Tunnel (now renamed Tom Lantos Tunnel), where the firm provided Integrated On-Site Team Support Services for the construction of twin 8,000-ft SEM tunnels and cross passages for Caltrans.

GZ is participating in three landmark projects in California – the VTA’s BART Silicon Valley Phase II Extension in San Jose, the Portal Project, and until recently the California High Speed Rail line, which will link San Francisco and Los Angeles and beyond. For the BART Silicon Valley project, GZ is acting as a subject matter expert for the VTA Board of Directors overseeing the work. For the Portal Project, also known as the Downtown Rail Extension (DTX), GZ is providing to SFCTA, a project funding agency, oversight, technical and managerial reviews and is acting as subject matter experts in support of SFCTA and TJPA. GZ was part of the Rail Delivery Partner team with WSP on the California High Speed Rail program since its inception, which includes 800 miles of train service and up to approximately 60 miles of tunneling. At the same time and with equal enthusiasm GZ is participating often in small and medium size projects in the West Coast similarly challenging including several projects in Seattle, and Los Angeles

The firm opened its London office in 2006 in anticipation of renewed infrastructure investment that included Crossrail and the High Speed 2 (HS2) railway. Crossrail, for which GZ provided services for the detailed design, specifications, contract documents and construction strategy of the project’s five SCL/NATM underground stations, was an approximately £20 billion rail line spanning 12.5 miles under the heart of London. High Speed 2, currently under construction, connects London and Birmingham. GZ is providing engineering and construction services and independent checking services on separate contracts for the Align JV (Bouygues-Volker Fitzpatrick-Sir Robert McAlpine JV), and the Balfour Beatty-Vinci JV, respectively. 

Meanwhile the company’s staff has grown accordingly, with the addition of young engineers and industry veterans. “One unique aspect of the company is the quality of the work and the quality of its people,” said Nasri Munfah, a principal with the firm and an industry veteran who joined GZ in 2021. “We provide the right solution for each project, whether it is state-of-the-art technical approaches or tried-and-true methods. We value our relationships with clients and foster a collaborative approach. These approaches have allowed the company to be successful for all these years.” In fact, that has allowed the company to earn repeat business from clients, according to Dominic Reda, a partner with the firm who started out as a summer intern in 2007. “Whether we are part of the program team or called in as a subconsultant for a specific task, our mission is to provide high quality work,” Reda says. “As a result, we are often requested by clients to be part of their future jobs.”

Niche

One of the keys to the success of GZ, according to its management team, is that it delivers specialty knowledge to augment the large engineering firms that are often brought in by clients to provide a board range of services across multiple disciplines. 

“Niche companies like GZ and the large engineering companies often play complementary roles,” Gall said. “The large companies are able to provide the overview framework for major infrastructure projects, with our supplementary expertise in underground construction – that’s where we come in. We are working internationally across a wide range of projects and that puts us in a position to bring the most up-to-date global solutions to clients in the U.S.”

“We don’t see ourselves as competition to the big companies, but rather as a good addition,” Zeidler added. “In some cases, they can’t afford to maintain specialty departments because that area of the business may by cyclical. We are able to come in as needed and solve a particular problem for the client, which helps streamline their operations.”

GZ’s geographic and disciplinary footprint gives its engineers insights when challenging problems arise, says Vojtech Ernst Gall, senior tunnel engineer. “In Chile we worked on rock burst analyses for a 2,000-ft deep cavern in the Andes for a mining project. There are very few deep rock tunneling projects in the United States, so this experience gives us a unique perspective when it comes to civil infrastructure. Likewise on the civil side, since we are active on a variety of jobs across different geologies, we can draw on that experience when we encounter difficult ground conditions wherever we are working.”

In addition to working internationally on a range of projects, GZ keeps abreast of the latest in tunneling technology by participating in various industry forums. GZ leaders are active in the Underground Construction Association and the International Tunnelling and Underground Space Association, are frequent lecturers at conferences and short courses, and have contributed to industry manuals and standards.

Future

As Gall Zeidler Consultants enters its next chapter, the firm is ready for growth and the transition to the next generation. While the staff has grown over the last two and half decades to include the next generation of leaders, the transition will be gradual.

“Right now, company leadership is a mix of current leaders and the new generation,” Gall said. “As we transition the know-how, we look forward to the new leadership taking over. But in the meantime, the current leadership – including Kurt, Nasri and myself – will continue to serve the company, providing our knowledge and experience as that transition gradually happens.” 

With the company involved on multi-billion dollar, multi-year programs, including Gateway, VTA, and the Portal, continued growth is likely. “Our philosophy is that growth is healthy,” Vojtech Ernst Gall said. “We want to continue to grow while maintaining our high quality of work. Our main focus has to be on maintaining a high quality of technical work.” 

With the company’s philosophy of fostering, training, and developing its employees, its growth will be from within. “Our vision is to deliver sustainable infrastructure solutions within an inclusive and diverse workplace,” said Munfah, “our employees are not workers, rather they are members of a family. They are included in company’s strategic planning, workshops, and events, and their voices are heard.” 

The future of the tunneling industry is bright. Increasing population and urbanization will continue to drive demand, while other factors including building resilient infrastructure in response to climate change and public demand for building underground are also good signs for the industry. In that framework GZ continues to foster novel methods for tunneling.

“The ITA forecasts that by 2050, 70 percent of the world population will be living in cities, driving the need to create new infrastructure in urban environments,” Gall said. “That provides opportunities in the market where we excel, namely urban tunneling in challenging conditions, the need for ground improvement and working around existing infrastructure. This bodes well for the growth of companies like ours in terms of our ability grow in the future.”