The Gautrain is an 80-kilometre (50 mi) mass rapid transit railway system in Gauteng Province, South Africa, which links Johannesburg, Pretoria, and OR Tambo International Airport. It was built to relieve the traffic congestion in the Johannesburg–Pretoria traffic corridor and offer commuters a viable alternative to road transport, as Johannesburg has limited public transport infrastructure. The project was completed with the opening on 7 June 2012 of the final section between Rosebank and Johannesburg Park Station, which had been delayed by problems with excess water seeping into the tunnel between the two stations.