ValleyMetro used a design-build procurement to complete the Central Mesa Extension. Terracon, as a subconsultant to the lead designer Parsons Transportation Group, was team member of Valley Transit Constructors (VTC) a Kiewit/Mass. Electric joint venture who completed the $200 million design build project. The 3.1-mile, million Central Mesa light rail extension extended previously constructed dual tracks from near Sycamore to east of Mesa Drive. The new tracks were constructed along the center of Main Street; additionally, four stations were built along this portion of the alignment. A park and ride facility was included at the Mesa Drive intersection. Appurtenant structures included three traction power substations (TPSS) and four signal houses. Terracon's geotechnical scope of work included borings in Main Street along the track alignment, park and ride, at the offsite substation and signal house locations, field resistivity testing, and a pavement condition survey of Main Street within the project limits. Geotechnical engineering analyses included developing subgrade support options and design parameters for the light rail track slab, shallow foundation design for station platforms and signal house structures, drilled shaft foundation design for overhead contact system (OCS) pole support, and developing mat foundation design parameters for the traction power substations.