Norfolk Southern Railway Company (NS) drew on its longtime relationship with Hanson when an extension was needed on its siding in Catherine, Alabama. The project was part of a grant-funded effort to relieve freight traffic congestion due to industry growth and shipment volume via rail in that state.

The project entailed the design of a new four-span, 116-foot-long bridge over Slater Creek, which is adjacent to the mainline bridge; grading a new track bed, access roadways, signal and centralized traffic control infrastructure; and permit preparation and determining temporary construction easement limits and real estate negotiation right of way for the Alabama Department of Transportation.

Hanson’s work scope included:

  • surveying
  • geotechnical engineering
  • civil and track design
  • bridge design
  • utility coordination
  • identification of real estate engineering requirements
  • state highway permitting coordination
  • entrance and roadway design at grade crossings
  • drainage structure design
  • grading design
  • structural design
  • hydrology and hydraulics
  • bid sheet preparation
  • National Pollutant Discharge Elimination System permit application

The design included 3,140 track feet (TF) of wood tie, continuously welded rail track; 110 TF of realigned and surfaced existing track; removal of the No. 15 turnout; conversion of the No. 15 turnout to power; and a new, 160-TF track panel and buttressing of a potential new control point location.

Challenges and solutions

During the construction of the new bridge across Slater Creek, the project team encountered previous grout roadbed stabilization while driving sheet piling for temporary shoring, which required a cutoff of the sheet pile prior to passing of train traffic. Hanson analyzed an alternate to the full-depth sheet piling and use of tiebacks before excavation to accommodate the new bridge construction.

During the pile driving, the team found an additional obstacle — this time, an unforeseen, unusual geological formation. After engaging with the contractor, Hanson and NS personnel arrived at a solution to perform minimal excavation and drive through the formation while maintaining pile integrity.