Heat may have played a role in DART rail delays in downtown Dallas, agency says

The high temperatures this summer may have played a role in delays for DART rails in downtown Dallas.

The transit agency sent out alerts about delays on all its rail lines a little after 7 p.m. Tuesday due to an incident near the West End Station. DART spokesman Gordon Shattles said that a damaged overhead catenary line near the station was to blame, and that it was harmed by the excessive heat.

DART operations were back to normal Wednesday morning, Shattles said.

The damaged line caused delays throughout the central business district, he said, and shuttle buses and a train shuttle are in place for passengers.

Catenary lines are a system of overhead wires used to supply electricity to the light rail vehicles, which are equipped with a pantograph. The pantograph, attached to the roof of the vehicle, presses against the underside of the lowest overhead wire, the contact wire, according to the Southeastern Pennsylvania Transportation Authority.

Shattles said the overhead catenary lines are across the entire rail alignment.

“The high temperatures can cause the metal in the catenary to expand, allowing the lines to sag,” Shattles said.

He added that as the train passes through, the damaged wire can become entangled with the pantograph attached to the train, causing further issues.

Shattles said that rail operations teams responded for repairs. Alternative routes and shuttles were communicated during the outage.

Dallas has recorded 24 days where the high temperature hit 100 degrees or higher — 18 of those were in July. Tuesday’s high was 107 at about 3 p.m., tying a previous record high for Aug. 1, set in 2011.

The hottest day of the year was July 18, when the high reached 108 degrees. There’s no sign of triple-digit temperatures ending until at least next Tuesday, according to a KXAS-TV (NBC5) forecast.