Group chief executive Mr Lucky Montana was fired on July 15 by the Prasa board after it said it was unhappy with his continued criticism of it, according to local media reports. Montana, who was already serving his notice period after resigning earlier this year, was shown the door after allegedly flouting the terms of an agreement which barred him from hiring or dismissing staff, or making procurement decisions, BDlive reports.

Montana told reporters at a press conference on July 17 that his sacking was unlawful but declined to give further details.

On July 17 the board also suspended Mr Daniel Mtimkulu, the Prasa engineer overseeing its Rand 4.8bn ($US 487m) locomotive deal with Vossloh, after an internal investigation revealed he did not have certain engineering qualifications that he claimed to.

The board said neither move was related to the current controversy around the deal for 20 Afro 4000 diesel-electric locomotives and 50 Euro Dual hybrid locomotives, which were ordered to help revamp Prasa's ailing Shosholoza Meyl long-distance services.

So far 13 of the Afro 4000 locomotives have arrived from Spain and are undergoing testing amid unrelenting rumours in the media that they exceed the South African loading gauge and may damage the electrification equipment on the country's extensive 3kV dc network.

Both Prasa and Transnet Freight Rail, over whose network the locomotives will operate, have consistently denied there is a problem.

However, the issue was raised earlier this month by opposition spokesmen in parliament. Prasa responded by holding a press conference, with Montana insisting reports in a weekend newspaper that the locomotives are out-of-gauge are incorrect.

Meanwhile, the cost of the deal has soared from an initial price of Rand 3.5bn after Prasa failed to hedge adequately against the South African currency's decline against the euro.

Later on July 17 evening, a MetroRail train packed with commuters ran into the back of stationary train at Booysens, south of Johannesburg, injuring 239 people, 100 of them seriously. The collision was caused by signal failure, according to a report from the independent Railway Safety Regulator.

This is MetroRail's second accident in recent months. On April 28, a Business Express train from Pretoria slammed into the back of another MetroRail train at Denver station, east of Johannesburg. A Prasa security guard was killed and 245 passengers were injured.

The investigation into the collision continues although earlier reports claimed the Business Express passed a signal at danger.