New Rio metro line to work at half capacity during Olympics

The 16-kiometer (10-mile) long extension to Line 4 was supposed to be running at full tilt in time for South America's first Olympics, which begin on Aug. 5 and run until Aug. 21. Yet, the delayed opening now scheduled for Aug. 1 is not a setback, Goulart said.

"This is a small adjustment and you can't call it a delay," he told Reuters. "I am guaranteeing operational security at the start of Line 4's operation. No one opens a line at full capacity."

Initially, only Olympic officials, ticket holders and others connected with the official event will be permitted to use the line connecting the populous South Zone of Copacabana and Ipanema to the neighbourhood where the main cluster of events will take place.

It will hopefully be open to the general public after September's Paraolympics, he said. Until then the new line will work at half capacity, or around 11,000 passengers per day, he said.

"We had a problem with financing and the chronogram was too tight but the metro will be delivered," Rio's governor Luiz Fernando Pezao added.

The metro line for the Olympics was one of the key infrastructure promises made by the city. But like the promise to reduce the amount of sewage in the water where sailing events will take place it is a promise that now will not be kept.

The announcement comes just weeks after part of another legacy project, a beachside cycle path, crashed into the sea killing two cyclists.

The delay is reminiscent of the 2014 World Cup that was also hosted by Brazil. Many of the stadiums were delivered late and several transportation projects were never built.