Brazil has become a country engulfed in major transportation projects ahead of the 2014 World Cup and 2016 Olympics in Rio de Janeiro—including subways, ports and a beltway to ease congestion in and around São Paulo.

In the past few weeks, however, the South American giant has become engulfed in some of the biggest protests in 20 years. Apparently sparked by a proposed increase in bus fares in São Paulo, which is known for its unreliable bus service, some 65,000 citizens there recently took to the streets to demand better public services and protest the state of transportation systems. Some 100,000 reportedly followed suit in Rio.

Construction and engineering experts say the country has stumbled after years of sprinting to expand its energy and transportation infrastructure. A sluggish economy has only slowed efforts to build new highways that could help Brazil shake its reputation as home to some of the world's most stunning natural beauty—and worst traffic jams.

"Brazil has not historically been known as a country with good planning," notes Adherbal da Costa Morreira, a director of operations for construction giant Camargo Corrêa SA, whose projects include the Belo Monte hydroelectric dam project in the state of Pará. "But we're getting better," he adds. The government's $66-billion stimulus investment in transportation, launched in 2012, is destined to change the country.

TBM in Rio, a New Ring for SP, Expanded Highways

São Paulo, for example, is adding more sections to its 177-kilometer "ring highway" project that eventually will connect the city's 10 major highways to the beltway surrounding it. Currently, trucks from the port to the west of São Paulo have to snake their way through metropolitan streets to get to highways outside the city of 11 million. New southern portions of the beltway will cut typical three-hour travel times in half, says Marcelo Garcio de Lima, a Contern consortium engineer on the project. When the entire highway project is completed, it will remove an estimated 300,000 vehicles from the 1.1 million that travel in and out of the city each day.

By September, the winning bids are expected to be announced on Brazil's R$16.5 billion, 500-km (317-mile) railway project linking the cities of Rio de Janeiro, Campinas and São Paulo. Construction would begin later this year and is expected to be done ahead of the World Cup in 2014. According to McGraw Hill Construction Dodge, the rail system involves construction of 90.9 km of tunnels, another 107.8 km of bridges and viaducts to traverse the rivers and mountainous terrain that separate São Paulo from Rio de Janeiro.

Meanwhile, in Rio Rio de Janeiro, about 6,000 workers are working on the Linha 4 Sul new subway line that will connect Rio's Barra da Tijuca section in the west to the city's eastern sections where many tourists visit and many residents work.

This month, crews began assembling a tunnel-boring machine—a first for Rio—that is slated to begin an estimated 4,600 m of excavation that includes tunneling under the world famous Ipanema and Cobacabana neighborhoods in October.

Lead contractor Odebrecht says the TBM, which officials here have named Barbara, is a convertible earth pressure balance (EPB) shield designed for excavation of two soil types. Alexandre Mahfuz, an engineer for the project, says the 11.6-meter-dia machine will excavate the first 300 m of the tunnel through the predominant gneiss in open mode, tunnel through sandy soil formations in closed EPB mode and then switch back to open mode.

When completed in 2015, the No. 4 subway line will join a transit system that now includes cable cars that have opened the city's formerly remote slums in the Complexo do Alemão favelas to downtown Rio. Six stations and 152 gondolas are equipped to carry some 30,000 passengers a day.

The $4-billion No. 4 subway project is a critical part of Rio's plans for the Olympics. Aluisio de Abreau Coutinho Jr, a project manager for the No. 4 line, adds, "But it's also important for the growth of the country and city."

Click here to see images of some infrastructure projects in Rio.