Transactions of the American Society of Civil Engineers, vol. LXVIII, Sept. 1910: The Bergen Hill Tunnels. Paper No. 1154

In Short

F. Lavis presents a authoritative engineering paper detailing the design, excavation, and concrete lining of the twin-track Bergen Hill Tunnels for the Pennsylvania Railroad’s New York Extension. Spanning 5,920 feet through dense trap rock between 1905 and 1908, the project overcame early contractor insolvency, severe compressed-air shortages, and complex geological water issues. Lavis documents every operational aspect, from drill patterns and powder charges to labor costs and concrete forms. It remains a classic record of early twentieth-century heavy civil engineering, preserved for its extraordinary empirical clarity and methodical technical discipline.

The Story

The narrative follows the physical and administrative progress of Section "K" of the Pennsylvania Railroad’s monumental entry into New York City: the 5,920-foot twin tunnels driven through the hard trap rock of Bergen Hill, ascending at a 1.3% grade from Weehawken to the Hackensack portal. Work begins in March 1905 under the John Shields Construction Company, but the enterprise stalls in early 1906 when the contractor enters receivership. Contractor William Bradley assumes the re-let contract in March 1906, inheritance-bound to severe mechanical bottlenecks, particularly an inadequate compressed-air plant that starves the rock drills down to 50 pounds of pressure.

To revive progress, the engineering management secures supplemental compressed air from neighboring river tunnel works, eventually installing high-pressure Corliss compressors that consistently maintain 90 to 100 pounds of pressure. Operations proceed simultaneously across multiple working faces driven from Weehawken, the 212-foot Central Shaft, and the Hackensack portal. Crews employ dynamic blasting methods, trying various small and large top-heading strategies. They record drill steel wear, dynamite consumption, and mucking rates while steam shovels and small "dinky" locomotives clear thousands of tons of rock—exceeding required section limits by over twenty-five percent due to core-wall breakage.

Once workers hole through the rock, the focus shifts to lining the parallel bores with concrete and waterproofing the structure against subterranean seepage. Engineers experiment with belt conveyors, Stuebner buckets, and custom cars before settling on traveling gantries and Hains mixers positioned at the portals. They install six-ply pitch-and-felt waterproofing mats along wet rock sections, lay thousands of feet of electrical duct conduits using specialized mandrels and iron rods, and erect smooth concrete arches on hard pine or steel forms. Openings like cross-passages and circuit-breaker chambers are built right into the structure, turning an accidental rock blowout in the central core-wall into a useful underground storage room.

The project finishes on December 31, 1908. Detailed progress profiles, daily inspector charts, and cost logs track every step, creating a comprehensive permanent record of a major American civil engineering feat.

How It Unfolds

The route is staked Engineers lay out twin single-track tunnels running N. 50° 30' W. along 32d Street produced, descending 64 feet below high water at Weehawken and rising to 17 feet above at the Hackensack portal.

Contractors swap places The initial contractor abandons the work in early 1906 following financial collapse, forcing a two-month stoppage until William Bradley takes over to complete the three-year excavation.

Air supply restored Severe air pressure drops halt drill performance until engineers strike a deal to pipe in 4,000 cubic feet of free air per minute from neighboring river tunnel plants.

Blasting through trap Crews drill and blast through hard sandstone and dense diabase, testing multiple cut-hole configurations while tracking steel loss, dynamite sticks, and daily linear advance.

Mucking and hauling Steam shovels load shattered muck into four-yard dump cars, which small tunnel locomotives haul out to portals or Central Shaft elevators for disposal and crushing.

Placing the concrete arch Workers move traveling gantries along the bench-walls, pouring concrete into polished steel and clear hard-pine forms to construct smooth interior arches and electrical duct banks.

Managing the water Crews seal leaking rock faces using six-ply pitch-and-felt mats, brick armor courses, and continuous rock-packing drainage channels that divert water to portal pumps.

Final inspection completed Alignment teams and inspectors complete final rodding of duct lines, surface finish checks, and granite masonry work on the Hackensack portal.

The People

F. Lavis The author and civil engineer who records every quantitative detail of the construction process. He seeks absolute technical accuracy to provide future engineers with reliable comparative data on drill performance, material costs, and labor organization.

William Bradley The secondary contractor who takes over the abandoned project in March 1906. Facing inadequate equipment and bad underground ventilation, he reorganizes compressed-air supplies, boiler capacity, and shift schedules to drive the tunnels to completion by late 1908.

J. R. Taft The Assistant Engineer in direct charge of tunnel construction. He manages field operations, oversees shifting contractor organizations, and coordinates daily structural work across multiple working faces.

R. L. Reynolds The Assistant Engineer leading the alignment party. He is responsible for precise field surveys, weekly progress profiling in multi-colored inks, and ensuring the opposing heading faces meet accurately deep inside the ridge.

J. S. Frazer The Chief Inspector who supervises approximately three-quarters of the tunnel lining operations. He manages tunnel, mixer, and conduit inspectors to ensure concrete surfaces and waterproofing match engineering specifications without costly post-pour finishing.

In Its Own Voice

"The total time elapsed from the time of starting work at the Weehawken end, in May, 1905, to the completion of the excavation, in May, 1908, was almost exactly three years."

Lavis outlines the overall temporal scope of the excavation phase before detailing specific daily progress averages.

"In all the foregoing tables and computations, the quantities used have been those paid for."

The author clarifies the economic baseline of his measurement tables, noting that actual excavated rock exceeded paid quantities by ten percent.

"The surface of the bench-walls was obtained solely by spading the face with a flat spade as the work progressed."

Lavis describes the practical field technique used to create a smooth concrete finish without expensive post-pour treatments.

What It's Really About

The paper explores how systematic organization, empirical tracking, and flexible field management overcome unpredictable underground conditions. Beyond the physical task of blasting through hard diabase, Lavis focuses on operational efficiency—balancing compressed-air pressures, drill hole geometry, powder charges, and laborer shifts to maintain steady progress.

It also examines the realities of large-scale public work, where theoretical plans face contractor bankruptcy, equipment breakdowns, water leaks, and material limits. Lavis shows that successful engineering relies on rigorous data collection. Daily progress charts, alignment surveys, and unit-cost accounting turn messy physical labor into a predictable, controlled process.

Why Read It Today

This work appeals to readers fascinated by industrial history, mega-infrastructure projects, and practical engineering. Reading it feels like looking over the shoulder of a master project manager at the turn of the twentieth century. There are no dramatic flourishes or sanitized summaries—just a clear, transparent record of how big projects were actually built.

The text requires patience with technical jargon, drill spec tables, unit cost breakdowns, and structural measurements. Yet this density gives the account its lasting charm. Lavis preserves the human effort through exact crew counts, drill runner pay scales ($3.50 a day), and practical fixes—like turning an accidental rock blowout into a permanent storage room or replacing breaking wooden rods with iron pipe. It stands as a grounded, honest record of the quiet discipline behind the infrastructure we take for granted today.