High temperatures throughout the Bay Area caused track-side control problems that at their peak around 4:30 p.m. were up to 45 minutes, according to BART multi-media managing producer Jim Allison.
By 6:15 p.m., trains were still delayed up to 30 minutes but the system was "improving and recovering," Allison said.
The spokesman said that as the temperatures were dropping, the "problems are being resolved and the equipment is operating better."
BART riders were being advised to board trains heading in the correct direction and follow instructions regarding transfers that were being announced on the trains.