The New York City Hudson Yards development project is one of the largest developments in the United States under the direction of some of the most prominent real estate owners/developers. An active 30 track railyard sits below the development. Cefali provided construction engineering services for the excavation of the No. 7 Subway extension station. This extension moves the last stop of the Queens line to the Hudson site. Under the instruction of Tutor Perini, Cefali evolved the basic geotechnical earth support system into a constructible scheme comprised of a massive secant pile wall braced by walers and tiebacks socketed into the granite bedrock. Hundreds of ties were coordinated with the project’s 300 caissons that were being installed before, during and after tieback installation. Boring logs were used to plot the top of the sound rock, helping to accurately predict the extent of the vertical shaft drilling and optimization of the waler and tieback system.