Engineers had to reduce the maximum speed of trains by 10 mph because the heat could cause kinks to develop in the rails.
The heat also caused switching problems.
Maintenance crews were monitoring both the rails and the switches.
Delays were expected on:
- The Union Pacific West Line to Elburn
- The Milwaukee District Lines to Elgin and Fox Lake
- The North Central Service to Antioch.
Metra officials said a switching problem at the A2 interlocker just east of Metra's Western Avenue stop was causing the delays.