This project involved the replacement of a main span through-plate girder (TPG) with a new welded steel TPG superstructure for NICTD's North Track (Track 2) while Track 1 remained in service. The bridge repair and replacement was completed over a live CN rail line while the superstructure repairs were completed under live NICTD overhead traffic.

The original plans called for on-the-ground bridge preconstruction. ICC negotiated a full 16-hour network outage window to enable the construction to be done in place, saving significant time and costs to the Owner. The existing span removal and new superstructure installation were completed using rapid insertion techniques with crane lifts that minimized impact on the CN line within two six-hour outage windows.

All work on the project, including punch list items, was completed two days in advance of the target completion date.

PROJECT HIGHLIGHTS

• Demolition and reconstruction of NICTD commuter line bridge over live CN freight line
• Coordinated precise network outage windows with CN directly on behalf of NICTD
• Worked with NICTD to take advantage of a down-line CN network outage
• Utilized specialized crane lifts for rapid insertion to minimize impact on the CN network
• Worked around major utilities onsite
• All work completed two days ahead of schedule