Rio State Transportation Secretary Rodrigo Vieira told Xinhua that local people are satisfied with the quality of Chinese trains.

"The subway trains have been operational in Rio's subway line 1 and 2, and we can say the local people 100 percent accept and welcome the trains. Therefore the majority of trains we use in Olympic subway line are from China," he said.

"Line 4 will contribute to making the Rio de Janeiro Olympic Games the best in history and will become an important legacy for the city, improving the quality of life of the people who live here," he added.

The Changchun Railway Vehicles Co belongs to China CRRC Corp Ltd, one of China's biggest train makers. CRRC started to research the Latin American market in 2004. Three years later, when Rio was chosen to host the 2014 World Cup, the government of Rio vowed to improve the city's rail network.

In 2009, when Rio won the contract for the Olympics, the city government eventually began to sign contracts with CRRC for the China-made vehicles, with CRRC selected over Siemens and Alstom.

CRRC was first given orders for 30 EMUs. After the first specially designed subway train arrived in Brazil in March 2012, CRRC won another 70 EMU orders because of the train's high performance and comfortable interior.

Over the past few years, CRRC provided 100 EMUs for Rio, and its vehicles will make up 82 percent of Rio's urban mass transit. It will also mark the first time that a Chinese train maker has taken part in an Olympic transportation system outside of China. To meet bid requirements and win contracts, CRRC offered more high-tech, cost-efficient solutions and special adjustments to meet Rio's needs.

The state and the city of Rio are investing heavily in transport infrastructure ahead of the Games. At the beginning of last week, Rio's international airport opened a new building that has almost doubled its passenger capacity. Last Saturday (28 May), the road linking Barra to southern Rio was expanded, increasing its traffic capacity by 30 per cent. On June 5, a new light rail system also begin operating in the centre of the city.