The Utah Transit Authority is about to replace aging tracks and switches in downtown Salt Lake City that will create a month of delays for TRAX passengers — who will need to transfer to shuttles or walk around construction to other stations.

It will also block or complicate some east-west traffic downtown, and sometimes impede access to Interstate 15 via 400 South.

“This is probably our most significant repair project since TRAX first opened in December 1999,” said UTA Chief Operating Officer Eddy Cumins, saying it is needed to guarantee safety and reliability after 18 years of wear and tear.

“This is a disruption to everyone’s traffic routes,” said UTA communications specialist James Larson.

Specifically, it will replace large curves and switches — which wear out quicker than other track sections — at 400 South and Main Street and at 150 South and Main. The $8.4 million project will start May 4 and is expected to be finished on June 2. Crews will be working around the clock every day during that month.

That “will allow us to complete the project in just four weeks as opposed to months of ongoing disruption” if UTA attempted to do the work only on weekends or late at night, Cumins said.

(Photo courtesy of Utah Transit Authority) UTA is about to replace worn-out tracks and switches in downtown Salt Lake City, which is expected to cause delays and detours for passengers and car drivers.

Still, it will create delays estimated at 10 to 30 minutes per trip for TRAX passengers who travel through downtown, and force detours for many cars there. However, Cumins said all businesses will remain open and accessible during the project.

UTA Project Manager Greg Thorpe said the agency chose to do the work after the end of spring semester classes at the University of Utah and before the city’s pride parade on June 2, saying the city had large events at most other weekends beyond that.

UTA will post changes to TRAX and bus schedules forced by the work — and routes of temporary shuttles around it — online at rideuta.com/construction. It will also have volunteers at stations, pamphlets and signs along highways.

Construction will come in four phases, and each will create different challenges:

• Pre-construction from now through May 3. Some preparatory construction around the intersection of 400 South and Main Street will take place nightly between 11 p.m. and 5 a.m. — and road closures are possible. Roads will be open at other hours. Mobile sound screens will be used to reduce noice.

• Phase 1 from May 4-22. Construction begins 24 hours a day at the intersection of 400 South and Main. It will block east-west traffic on 400 South, complicating access to the freeway.

TRAX riders using the Red Line will need to walk or ride shuttles between the Courthouse station and a temporary station on State Street to continue service.

UTA suggests that FrontRunner passengers headed to the University of Utah may want to exit at the Salt Lake City Central station and take bus routes 2, 2X, 3 or 11 to the university, instead of taking TRAX.

Blue Line TRAX riders will need to walk or ride shuttles between the Courthouse and Gallivan Center stations. UTA says Green Line riders will need to transfer to the Blue Line at the Central Pointe station at 2100 South, and then follow the same connections as Blue Line riders.

Phase 2 from May 23-28: For five days, construction will occur both at 400 S. Main and 150 S. Main. So shuttles around work areas — or pedestrian paths — will be longer.

• Phase 3 from May 28 to June 2: Construction will only be ongoing at 150 S. Main. So 400 South will be open. The TRAX Red Line will stop at all its stations. Riders on other lines will need to walk or take shuttles between Gallivan Center and the City Center station.

Also in July, UTA will replace another switch and curve by Vivint Smarthome Arena at the corner of 400 West and South Temple. Thorpe said that work will happen on weekends, and will be less disruptive.