Commuters can expect delays on the Gautrain line on Thursday because of cable theft, the company tweeted.
"Due to cable theft, trains to OR Tambo will operate on a single track.
"Expect your journey to be extended by approximately 20 minutes in the peak period (headway will be approximately 30 minutes instead of 10 minutes).
"We will inform you once trains are operating according to schedule again," Gautrain said.
Cable theft has caused delays in Gautrain schedules before, most recently in June and March last year.
There was no indication when trains would be operating according to schedule again.