The Sishen–Saldanha railway line, also known as the Ore Export Line (OREX), is an 861-kilometre-long (535 mi) heavy-haul railway line in South Africa. It connects iron ore mines near Sishen in the Northern Cape with the port at Saldanha Bay in the Western Cape. It is used primarily to transport iron ore (60 million tonnes per year) and does not carry passenger traffic.

Railway electrification systems using alternating current (AC) at 25 kilovolts (kV) are used worldwide, especially for high-speed rail. It is usually supplied at the standard utility frequency, which simplifies traction substations. The development of 25 kV AC electrification is closely connected with that of successfully using utility frequency.