Learn how Brierley built a 12×12' jacked box tunnel under active rail to close the Empire Trail gap using trenchless tech.

Learn how Brierley Engineering closed the final 3-mile gap in the 750-mile Empire State Trail by constructing a 12-ft x 12-ft pedestrian tunnel beneath three active railroad tracks—an area with only 5 feet of cover where a conventional circular tunnel was not feasible. To meet the tight constraints and protect the rail embankment, Brierley employed their innovative jacked box tunnel system, using a cast-in-place concrete box that was pulled, rather than pushed, through the embankment. This unique approach balanced forces from both sides to significantly reduce ground movement and maintain rail stability during construction. The team relied on trenchless technologies, including pilot tube guidance and horizontal directional drilling, to accurately install key components needed for the jacking operation. Working continuously over seven days, the box was successfully pulled into place, completing a crucial safe crossing for trail users. This presentation will explore the trenchless methods, engineering challenges, and the adaptability of this box-jacking technique to different site conditions across the country.