Caltrain trains are running 30 minutes late on the Peninsula after the software to switches on the tracks failed, according to transit officials.

The first report of a faulty switch between the Belmont and Hillsdale stations was reported around 6:30 p.m. Tuesday, according to Caltrain spokeswoman Christine Dunn.

The switch authorizes train operators to proceed through certain portions of tracks. The software failure was giving trains a red light and therefore conductors could not proceed. Instead, operators needed to gain verbal authorization and proceed through the area manually, Dun said.

What caused the switch to fail is under investigation. The switch was repaired just after 7 p.m., according to Dunn, but there are residual delays.

akoskey@sfexaminer.com