Staff in blue uniforms usher passengers into red cabins at Rio's train station Bonsucesso, some 15 kilometers (9 miles) from Rio de Janeiro's city center. As the doors close, the motorized carriages are lifted into the air, beginning their steep ascent to the next station. Below lays a vast mountainous landscape, dotted with tens of thousands of unevenly clustered red brick shanties.

Complexo do Alemao is a sprawling mass of 12 favelas, housing some 140,000 people in Rio de Janeiro's northern zone. While it might seem like an unlikely location, the community is home to a sophisticated cable car system capable of transporting up to 30,000 passengers a day.

"I use it every day, morning and night. I like everything about it. It helps me a lot," said 56-year-old resident Aline Gomes who works a cleaning job in Rio's center. "It's much easier, much better."

The teleferico, as locals call the cable car, serves six stops in the community along a 3.5-kilometer (2-mile) circuit. While it takes an hour to cover this distance by foot, the teleferico gets passengers there in 20 minutes.

Cheaper and more efficient

Residents are entitled to one free round-trip a day - if they need to ride more often, they have to pay 1 real (40 cent) for a trip.

"It makes things easier for me because I save money. A combi van [minibus] for example is double the price," said Celia de Souza, 59, who has lived in the community for 40 years and runs a small business selling bottled water and beer.

"It also makes it easier for when I go shopping and return with water and beer. I don't have to walk up these big hills with all of my shopping items."

Previously, Celia and Aline relied solely on the community's unofficial transport methods, such as mototaxis and Volkswagen combi vans. Now, they use those services simply to get to the nearest teleferico station.

The cable car project was funded by Brazil's Accelerated Growth program (PAC), a federal government initiative focusing on three main areas - social development, logistics and energy.

According to the government, the teleferico was built with the aim of improving transport for residents and attracting tourism.

There are two main ways the teleferico helps the community, explained Jorge Mario Jauregui, the architect who designed Rio's cable car. "First, by being a cheaper and more efficient transport system allowing them to access the formal city easier. Second, by attracting tourists who come to the community and help the local economy by consuming."

The teleferico was inaugurated in 2011, following a pacification scheme in which a permanent police presence was established after army and military police chased out drug lords who had dominated the community for decades.

Attracting tourists

Arriving at station Palmares, the end if the line, passengers disembark. Locals make their way down the hill while tourists walk out onto the station's concrete forecourt to take in the breathtaking view, where they are greeted by kids hawking refreshments. Some people have even set up shop here.

"It's not just a method of transportation, it's also something to do. It's fun," said Suzanne Lima, one of the first residents to set up a stall here.

The teleferico model at Rio's infamous favela Complexo do Alemao is based on a similar system functioning in Medellin, Colombia, that also serves a large hillside settlement.

Partly due to their low C02 emissions, cable cars are increasingly being looked to for urban transport. Another cable car is due to open in Rio's first and most historic favela - Morro da Providenica - in May.

However, critics of the systems have been quick to question the cost-to-benefit ratio.

The teleferico at Complexo do Alemao cost around $110 million (84 million euros), which has significantly depleted the community's development fund.

No funds for urgent projects

"I'm not going to say that the teleferico is worthless. But in my opinion, the money that was invested in the teleferico could have been invested in other areas," said resident Lauro Sidney, head of Grupo Socio Cultural Raizes em Movimento, an organization that has for the past 10 years given advice, consultations and workshops to those in the favelas' vast informal workforce.

"Basic sanitation is priority number one; next, cultural structures, structures that allow people in the community to develop professionally," Sidney added.

Resident associations in the community have expressed that they weren't properly consulted about the project. Other scheduled works, such as repairs to the exhausted and overstrained basic sewer system, remain unfinished.

The community continues to suffer from a serious lack of fully functioning basic services. Educational opportunities and health services are poor, at best. Daycare facilities for single mothers are non-existent, putting further strain on already impoverished families.