Cape Town - Angry commuters went on the rampage at Cape Town station over delayed trains on Monday night.
Thick black smoke could be seen billowing from the station a train was set alight on platform 15.
Metrorail spokesperson Riana Scott said there were some service problems.
Earlier, in a series of notices on Twitter, Metrorail announced delays of about an hour between Salt River and Woodstock on the Southern line, technical problems at Maitland and Woltemade on the Northern line, and technical problems between Ysterplaat and Esplanade.
@Just_ONeill tweeted: ''Ok guys, this is a riot happening here at the train station because of the delayed trains,'' and added a video of crowds gathered on the concourse.
@TrafficSA tweeted: Cape Town - Commuter Unrest at Cape Town Train Station - Public Order Police arriving
They posted a video in which people were shouting, with banging in the background.