Tetra Tech has provided design, transportation, hazardous materials management, environmental permitting services, and bridge design support for the commuter rail expansion of the Greenbush Line from Boston, Massachusetts, to the South Shore. Tetra Tech designed more than 20 traffic control signals, including five signals at highway-railroad grade crossings that required railroad preemption. Tetra Tech also designed all pavement markings and regulatory and warning signs. Stations include accommodations for bicycle parking and passenger dropoff/pick-up by automobile, van, or bus.

Nine existing single-span railroad bridges were reconstructed with new ballast deck superstructures and new or rehabilitated abutments and wing-walls. Work will be performed on two existing roadway bridges over the right-of-way, one to be replaced, while the other will be repaired. Tetra Tech also assisted in the Weymouth Landing Station boat section and bridge overpass designs.

Tetra Tech supported the permitting effort for the project by providing wetlands analyses and habitat evaluations during the design phase, in support of a Massachusetts Wetlands Protection Act Variance required for the project, and prepared Construction National Pollutant Discharge Elimination System (NPDES) applications and Storm Water Pollution Prevention Plans (SWPPP). The firm also provided compliance coordination during construction for wetlands and stormwater issues. Tetra Tech conducted hazardous materials investigations and developed a hazardous materials management plan.

Tetra Tech designed traffic management plans to minimize traveling disruptions and impacts upon the community during the multiple construction phases.