Repairs to cracks in steel rails along a $1.4-billion, 20-mile Phoenix-area light-rail project are nearly complete. The 33-station, at-grade METRO line, which runs through Phoenix, Tempe and Mesa, is still on track for a Dec. 27 debut.
Officials found fissures up to 7.5 in. long in three of the five segments during routine inspections. In January, METRO hired consultant Zeta-Tech Associates, Cherry Hill, N.J., for $60,000 to conduct a three-month investigation to determine the cause and recommend repairs. It found that high heat from handheld plasma welding torches used to cut drainage openings changed the steel’s structural properties, resulting in brittleness and microscopic cracks that worsened with expansion and contraction during seasonal weather changes.