Coordinated Power for Major NY State Bridge

Jack and Slide Offload

The Tappan Zee Bridge, a twin cable-stayed bridge spanning the Tappan Zee section of the Hudson River between Tarrytown and Nyack in New York, was decaying and in desperate need of replacement. The bridge’s 8 lanes carry heavy automobile traffic  as part of the New York State Thruway, Interstate 87 and I-287.  The bridge also carries a shared use path for bicycles and pedestrians.

Eaton’s Integrated Power Assembly (IPA) group invited Trachte to be part of the construction team because of an ongoing partnership and successful completion of multiple past projects. Trachte designed (2) E-houses for installation on both ends of the bridge, all to house critical power, control, and protection equipment for the operation of the bridge’s elaborate electrical scheme. Project challenges included an aggressive construction schedule, DOT travel permitting for the oversized E-houses, and coordination between two different utilities for the power system, each required to support the entire bridge system in the event of failure on either side.

Application Notes

  • Two E-houses designed and built to meet the standards as dictated by two separate local utilities.
  • Multi-split buildings: Building #1, 22′-10″ x 55′-0″ x 10′-8″ and Building #2, 24′-4″ x 63′-1″ x 10′-8″.
  • The first E-house was installed using a high-capacity crane.
  • The second E-house was located under the bridge and required a complex jack & slide system to offload and set the building.
  • Medium voltage switchgear and third-party control and protection equipment with fiber optic interface.
  • High level of switchgear interconnect cables for state of the art, automated operating equipment.
Crane Offload


Trachte shipped (2) multi-split buildings on time, even after navigating rural delivery routes, restrictive DOT permitting, and heavy traffic at different times of the day. On-time delivery meant a successful connection of medium voltage cables to the switchgear. Trachte’s extensive quality management, including the installation and verification of control terminating points, resulted in zero punch list items during site commissioning.