A joint venture (JV) of Fluor and Walsh Construction Company has finished the construction of a rail bypass structure, under the Chicago Transit Authority’s (CTA) Red and Purple Modernisation Phase One Project.

This infrastructure is expected to address congestion problems on the CTA’s Red, Purple and Brown lines.

With the passing of the first train on the Red-Purple bypass, this project has reached a major milestone for the improvement of CTA’s rail system.

Located in a dense commercial neighbourhood near Wrigley Field, this infrastructure is built on a 120t beam spanning the track structure below.

Incorporating ‘notable’ innovations, the Walsh-Fluor design-build team constructed a bridge with less support columns, along with structural strength.

This design not only cut down the schedule of construction but also had less impact on the surrounding area.

Fluor infrastructure business president Thomas Nilsson said: “Designing and building complex infrastructure projects in populous areas with limited impact to businesses, residents and commuters is a trademark of Fluor’s infrastructure business. When complete, this project will improve the quality, safety and reliability with an upgraded transit experience for CTA riders.”

The infrastructure can manage more trains and passengers per hour, enabling an increase in the traveling speed of the trains.

By replacing the steel structure, the bypass’ concrete, closed-deck track and sound walls will generate less track noise.

This $1.3bn project, expected to be finished in 2025, is said to be the ‘largest capital project’ for CTA.

In June this year, the JV started the reconstruction of the station house and track structure under the CTA’s Lawrence to Bryn Mawr Modernisation Project.