A 2-mile trench through central Fresno, traveling under State Route 180 (SR 180), a railroad spur, and Dry Creek Canal. This will be the first section of the alignment to go below grade, to a depth of approximately 40 feet, as drilling rigs bore foundations for the trench barrier walls that will separate high-speed trains from the adjacent freight trains.
From approximately Olive Avenue to Stanislaus Street. Work on the trench has begun south of Belmont Avenue along with excavation beneath SR 180.
A boring machine can be seen drilling about 80 feet into the trench walls under State Route 180 (SR 180), after which construction crews will install a steel tendon tie-back that is similar to a cable. Grout will then be injected into the hole and tensioned after it has gained strength. Crews will then excavate deeper and the process is repeated. The next phase of construction will shift eastbound traffic onto a temporary bridge that will allow further excavation. The tunneling operation should break through to the other side of SR 180 sometime in the beginning of next year.
Work began in July 2016 and will continue until late 2018.