The project included the replacement of the Union Pacific Railroad Bridge 3.49 over Ashland Ave. in Chicago, IL. The bridge carries eight yard tracks and one main track, perpendicular to the roadway. The scope of work included the removal of the existing bents and superstructure, as well as the construction of new precast abutment blocks, new bents supported by micropiles, and four new steel box girder spans, which consisted of two qty 11 LF spans and two qty 24.5 LF spans for each of the nine tracks.  The work was required to be performed with minimum interruption to rail yard service. As such, the project was completed in three phases, allowing for a minimum of three live tracks during the demolition and reconstruction process. Each phase consisted of a 72-hour track outage when the demolition, steel erection, waterproofing, and grading was performed