Parliament - The number of passenger trains on South African railway tracks subject to manual authorisation because of defective signalling systems continues to rise, MPs heard on Tuesday.

Briefing Parliament's portfolio committee on transport, the Rail Safety Regulator (RSR) acting chief executive Tshepo Kgare explained the rationale behind the suspension of the operating permit for the Passenger Rail Agency of South Africa (Prasa) following yet another train collision on October 4, which left 320 passengers injured. The crash was caused by a train being wrongfully manually authorised to continue on a track where another train was operating.

Kgare said they were left with no choice but to issue Prasa with a suspension notice after the rail agency had continually failed to provide the regulator with representations on how it would mitigate risks associated with the manual authorisation of trains where signalling systems, used to direct railway traffic and keep trains clear of each other, were not working.

The matter ended up in court with the RSR agreeing to rescind its suspension notice, subject to Prasa complying with all the regulator's safety requirements.

Since January this year, the number of trains being manually authorised had grown monthly, said Kgare, to 108 000 in September.