The department's deputy director general Mr Lanfranc Situma said last month that the 125km Pretoria - Moloto line would be the government's priority due to the high number of road fatalities on this route. The Rand 15bn ($US 1.8bn) project has already been registered as a PPP and approved by the cabinet.

The other three proposed high-speed corridors will radiate from Johannesburg to serve Durban, Polokwane, and Cape Town, although Situma says the Johannesburg - Durban line will only be viable if it carries freight traffic.