Utility Reconstruction for the University Light Rail Project

Utility Reconstruction for the University Light Rail Project

Eliminating utility infrastructure conflicts today will make light rail more reliable and efficient in the future.

Thomas Ward, P.E.

January 22, 2001

New Light Rail on Main Street.

Most Salt Lake residents know about the Utah Transit Authority (UTA) TRAX Light Rail line recently constructed from Sandy City to downtown Salt Lake City. Since going into operation late in 1999, ridership has exceeded expectations, and among other things, led to the decision to construct a spur to the University of Utah. The University Light Rail Track (University LRT) begins on Main Street and 400 South, terminating at the Rice-Eccles Stadium on 500 South (400/500 South alignment). Construction of the $75 million spur started last June and is scheduled to be completed by November 2001. Train operations should start in time for the 2002 Winter Olympic Games. TRAX is owned and operated by UTA.

What most Salt Lake residents may not know is that numerous water, sewer and storm drain pipelines are being replaced or relocated by UTA along the University LRT route.

Why Reconstruct Utilities for the University Light Rail Project?

Why expend all the time, effort and money to reconstruct utility infrastructure just because light rail will be running over the buried utilities? The answer: It provides a more reliable and efficient rail transportation system and protects the public untility infrastructure from damage and unnecessary expenses.

Light Rail transit system operations impose two unique changes upon utilities within the TRAX corridor:

The first and most obvious difference is that unlike cars or buses, light rail trains cannot be detoured around obstructions in the road when, for instance, a water line breaks. Utilities which lie underneath the tracks must be either relocated or improved to minimize the possibility of breaks and mitigate the need to tear up the road and shut down TRAX operations during routine or emergency utility maintenance.

The second, and less obvious impact of a new light rail system is a phenomena called stray current corrosion. Light Rail trains are powered by electricity. In basic terms, electrical current travels in a circuit from the power station to the train via the

The 36-inch main at 1200 East 500 South is shown being relocated with new corrosion protected pipe and a monitoring system.

overhead wires above the tracks, through the train’s electric engine, and back to the power station via the rail and ground. Electric current in the ground will use the most conductive medium to return to the power station. Iron and steel water pipes are often good conductors. However, when the current leaves the pipe, it takes electrons with it and corrodes the pipe. To mitigate this problem, UTA is constructing a state-of-the-art system to minimize any stray currents. Furthermore, new water lines are being constructed with plastic materials (PVC and high-density polyethylene pipe) and/or protective coatings. Included is a monitoring system to determine if any light rail stray current is getting onto the water pipes.

What utility work is UTA doing?

All water, sewer, and storm drain pipes which cross under the TRAX are being replaced and encased so that 1) stray current impacts are minimized, 2) future repairs are far off in the future, and 3) repairs, if needed, can be accomplished with little or no impact to light rail train operations. In addition to reconstruction of water, sewer and storm drain crossings at all 14 intersections along the 2.5 mile corridor from Main Street to the Rice-Eccles Stadium, several major water and storm drain pipelines that parallel under the TRAX alignment are being relocated. The most significant utility reconstruction element is the relocation of approximately ½ mile of 36-inch cast iron pipe on 500 South from 1000 East to 1350 East. This pipeline was installed in 1936 and is an important supply line to downtown Salt Lake City. The 36-inch pipe material is highly susceptible to stray current corrosion, making it necessary to relocate the line with new corrosion coated pipe and a monitoring system.

What does all this TRAX Utility Work mean to me?

Due to the extensive work on the water system, interruption of water service to customers along the TRAX corridor cannot be avoided. However, the contractor is required to solicit customer input regarding scheduling shutdowns, to inform, anticipate and mitigate impacts to businesses, residents and the public along the 400/500 South alignment. In addition to general public information media, the contractor is required to notify customers a minimum of 48-hours prior to utility shutdowns required for construction. “Our goal is no surprises,” says Katie Parker, public information specialist for the joint venture construction team. A 24-hour TRAX Hotline is in place for community members to call if there are questions or concerns. The 24-hour Hotline number is: 556-TRAX (8729).

Historical Note

Trolleys on Main Street in 1907.

Although light rail might seem to be a new form of transportation, it was the main transportation system at the turn of the twentieth century. At that time there was an extensive trolley system throughout the city. Originating from its home base located at Trolley Square (700 East 500 South), trolleys moved passengers throughout the city. In time the trolleys were replaced with buses and the tracks removed from the streets.

Lessons Learned

The Salt Lake City Water Department has records dating from that time documenting pipe breaks attributed to the electric trolley system. That’s why the utility infrastructure today is being relocated and protected. It’s the City’s and UTA’s intent to mitigate any light rail impacts to the City’s utility infrastructure while light rail is under construction and costs and disruptions are manageable.

More Information

Additional information regarding the University Light Rail Project can be obtained at www.utabus.com, or www.gofourth.com. If you have any questions or comments regarding this article or water, sewer or storm drain work for the University Light Rail project, please contact Tom Ward, SLC Public Utilities project manager (801-483-6884, thomas.ward@ci.slc.ut.us).