No major problems were found during a spot inspection of third rails that provide power to three major subway lines, according to the MBTA.
The inspection was ordered by T General Manager Beverly A. Scott after two cracks were discovered in the third rails at the JFK/UMass station on the Red Line on Tuesday night and Wednesday morning.
In an email, T spokeswoman Kelly Smith said inspectors focused their attention on areas with similar characteristics to the third rail that cracked in Dorchester. The inspections were conducted on the Red, Orange and Blue subway lines.
“They found nothing that would require immediate attention,’’ Smith said. “Personnel will continue to keep a close eye on the rails during this cold spell.’’
The third rail delivers electric power to the trains. The cracks are believed to have been caused by cold weather, which caused the metal to contract and fracture at the points where the rails were welded together. A crack in the rail is not dangerous — without power, trains simply come to a stop — but T officials intend to inspect the welding on third rails in the system to ensure that future cold spells do not cause the same disruptions.