The union said on Monday it was in the process of launching a court bid to force Prasa to adhere to safety standards.
Untu general secretary Steve Harris said more than 50% of the signals used by train crews were out of order because of theft and vandalism.
“Between January 11 and June 30, more than 320 000 manual train authorisations had been issued by Prasa. The number keeps on increasing, and there is no indication that Prasa is even attempting to normalise the situation,” said Steve Harris, general secretary of the United National Transport Union.
“Manual train authorisations (MTAs) make trains more exposed to collisions and derailments, as human error may occur, as what happened at the Geldenhuys station in Germiston on the East Rand in January, when three trains were authorised to continue the same route due to MTAs being used,” Harris said.
Untu has called on its members, who constitute more than half of Prasa’s workforce, to inform the union of each incident, irrespective of how serious it is, to allow the union to compile a comprehensive time line to bolster its case.
The union also hit out at Minister of Transport Blade Nzimande, accusing him of forcing the Railway Safety Regulator (RSR) to issue the rail agency with a temporary safety permit earlier this month.
The troubled rail agency briefly operated without a valid safety permit this month after its permit, which was previously issued with special conditions, expired at midnight on July 31. The temporary permit enabled Prasa to continue with its operations and to address the identified inadequacies.
Prasa has until Friday to come up with a safety plan for its commuters before its safety certificate expires.
Prasa found it impracticable to cease operations once its previous safety certificate expired. Ceasing operations would have meant almost two million commuters would not reach their destinations, and the inability of Transnet to traverse their network - costing the economy millions of rand.
Prasa spokesperson Nana Zenani said the company was committed to complying with safety standards and would not wilfully risk the lives of its employees and commuters.
Department of Transport spokesperson Ishmael Mnisi hit back at Untu’s allegations.
“The statement by Untu is reckless and unfounded. Nzimande has not issued a directive to the RSR to issue Prasa with a compliance permit,” Mnisi said.
“Rail safety is one of the tenets of providing a reliable metro rail service, and the minister will not issue a directive that will endanger or compromise the lives of the commuters and South Africans at large.”
The RSR could not be immediately reached for comment.
There have been a few rail accidents since the beginning of the year.
In January, a Shosholoza Meyl train en route from Port Elizabeth to Joburg crashed into a truck that had allegedly failed to stop at a level crossing.
The accident involved nine carriages. Eighteen people were killed and more than 200 passengers injured.
In May, four people were killed in a collision between a vehicle and a train in Magaliesburg, north-west of Joburg.
“The government remains responsible to abide by safety regulations where passenger rail is concerned.
“The government, as the custodian of all state-owned entities in our Constitution, is accountable when injuries occur,” said Jaco du Plessis, an independent attorney specialising in civil claims.