(CNN) Near Africa's horn on the easternmost part of the continent, a shiny new electric railway runs alongside an old abandoned track through both arid desert and green highlands.

Some 750 kilometres (466 miles) long, the $4 billion line connects landlocked Ethiopia to the Red Sea coast in Djibouti.

Officially inaugurated last week after test runs kicked off in October, it is expected to cut the travel time between the Ethiopian capital Addis Ababa and the port in Djibouti from three days by road to 12 hours by rail.

Like a number of other planned lines it was partly funded and built by Chinese companies. It could soon link up with neighboring Sudan and Kenya -- where the first part of a new $13 billion Kenyan railway connecting Mombasa to Nairobi is taking shape.

The sprawling network is planned to continue into South Sudan, Uganda, Rwanda and Burundi, as part of transnational efforts to connect countries within East Africa.

This could transform how goods and people move, and the increased number of lines is expected to boost trade in countries like Kenya, says Kuria Muchiru, advisory partner, East Africa, at PwC in Kenya

"Because we probably have about 4,000 trucks everyday making the trip up from Mombasa into Nairobi, and some go farther on," adds Muchiru.

The ports are where the magic happens, with 90% of African imports and exports conducted by sea which can be an issue for trade coming into landlocked countries.

"The new lines will have access to the ports and be able to almost offload directly onto the train and then straight onto inland locations," Muchiru says.

Billions in loans

The new lines are part of the so-called LAPPSET rail project and the EAC Rail Sector Enhancement Project, also called the East African Railway Masterplan, and managed by the East Africa Community (EAC) -- an intergovernmental organization run by Burundi, Kenya, Rwanda, South Sudan, Tanzania, and Uganda -- together with consulting company CPCS

But railways don't come cheap, and African countries are borrowing heavily from China to scrape the funds together.

In the 10-year period between 2004 and 2014, African countries borrowed nearly $10 billion for railway projects from China, facilitated by the China Export Import Bank (Exim), according to researchers by SAIS China Africa Research Initiative at Johns Hopkins School of Advanced International Studies (SAIS-CARI).

Why does China invest so enthusiastically?

China sees the railways as an investment opportunity which also creates an export market for their booming steel and construction industries, says Deborah Brautigam, professor of international political economy and director of SAIS-CARI.

"They have overcapacity in China. They have steel that they want to use. They've got experienced companies that know how to build railways."

But it's not without risks, and whether the loans will be fully repaid remains to be seen, she adds.

"That's still a question mark."

However, while countries often dream big, not all projects make it past the planning stage, according to Brautigam.

Between 2000 and 2011, the Chinese backed more than 1,700 projects, from buildings to dams in 50 African countries at a cost of $75bn.

Looking at larger projects, five railways have materialized so far, with the Tazara railway -- which links Tanzania and Zambia -- being the first to be completed back in the 1970s.

The other four projects are in Ethiopia, Nigeria, Kenya and Sudan, says Brautigam.

The West not as keen

The US and other Western countries have financed some railways and other infrastructure projects across the continent, but they haven't been as keen to invest as China, partly due to a fear that the African countries won't keep up the maintenance, Brautigam says.

"[They] have put some money into these railways but not very much. They really haven't wanted to finance them."

"They felt, and probably rightly, that these governments were not doing a good job with what they had already," she adds.

So are these new East African railway projects feasible? Andrew Grantham, editor at Railway Gazette International who covers railway developments in the area, says that as long as there are funds and political will, there are no technical hurdles to expect.

The Chinese-built Qinghai-Tibet railway spans 1,956km across high altitudes linking Xining in Qinghai Province to Lhasa.

"The Chinese have built a railway to Tibet, and once you've done that, very few things are going to be a technical challenge."

"If you have the right environments, there is no reason these schemes shouldn't happen," he adds.

While the old colonial lines vary in size and style, the new Chinese railways will be standardized, which makes it easier to link lines and countries, Grantham explains.

"Essentially, the Chinese will give you a catalogue. You pick one and build it."

Is China building everything in Africa?

It's not just railways. The Chinese are involved in constructing buildings, dams, and bridges within the continent.

Photos: Trillion dollar deals: The China-Africa partnership in pictures Bridging cultures – Trade and partnership deals between African countries and China have been steadily increasing in recent years. This summer saw the completion of Morocco's Mohammed VI Bridge, a $72m project built by Chinese development group Cover-Mbec. Hide Caption 1 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Whatever the weather – Chinese investment is the leading source of infrastructure spending in Africa. Nigeria accounts for the most umbrella imports, with trade worth $39 million in 2014. Hide Caption 2 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Access all areas – Trade has become increasingly diverse, as typified by recent deals to export elephants from Zimbabwe to China. President Robert Mugabe's government sold 24 elephants to Chinese zoos in 2015, and despite protests from animal welfare groups, the figure will climb again this year. Hide Caption 3 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Cost of smoking – In addition to elephants, Zimbabwe also exports vast quantities of raw tobacco to China. Sales reached a new peak of $575 million in 2014. In return, China supplies Zimbabwe with telephone equipment worth over $50 million, and a range of construction equipment. Hide Caption 4 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Ben-in disguise – Benin is the leading importer of wigs in Africa, spending $411 million in 2014 on Chinese-made fake hair. The tiny state was also by far the continent's largest buyer of cotton from China, worth $852 million. Hide Caption 5 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Exotic taste – Morocco supported one of the country's most popular habits with tea imports from China worth $211 million in 2014, the most of any African state. Hide Caption 6 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Right track – Ethiopia supplied its booming construction industry by importing railway track materials worth $60 million in 2014, the highest spend in Africa. Hide Caption 7 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Wealth kick – South Africa was the leading importer of bicycles in 2014, with trade valued at $23 million. Libya followed close behind with $11 million worth of Chinese bikes. Hide Caption 8 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Going overboard – Liberia imported ships worth a continent-high $833 million in 2014, in most cases through the famous port of Monrovia. Hide Caption 9 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Total coverage – China's scarves have found their largest African market in Egypt, which imported supplies worth $45 million in 2014. The nations also have a healthy exchange of carpets, with multi-million dollar supplies traveling in both directions. Hide Caption 10 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Holiday homes – A recent report from the Centre for Chinese Studies at Stellenbosch University in Cape Town documented increased Chinese investment in real estate in South Africa and Mauritius, worth around $740 million in the island state since 2005. Hide Caption 11 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Curtain call – China has also invested heavily in cultural projects across Africa. Theaters have been a priority area, including Senegal's new 1800-seat Grand National in Dakar (pictured), largely funded through Chinese aid. Hide Caption 12 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Stadium diplomacy – 'Stadium diplomacy' has been another feature of Chinese investment, with new arenas in Cameroon, Ghana, and Angola's November 11 stadium in Luanda (pictured). Hide Caption 13 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Medical aid – Dozens of African hospitals have been built with Chinese funds in recent years. President Xi Jinping inaugurated this hospital and a new university library in Brazzaville, Republic of Congo, in 2013. Hide Caption 14 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Strength in unity – The headquarters of the African Union in Addis Ababa, Ethiopia, was built with $200 million of Chinese state funds. Hide Caption 15 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Transport upgrades – China's largest commitments in Africa are to infrastructure projects, such as Nigeria's $8.3 billion Lagos-Kano rail line, largely funded through Chinese loans. Hide Caption 16 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Turning the tide – Ghana has been able to mitigate electricity shortages through the Bui Dam on its Western border, which incorporates a 400-megawatt hydropower plant. The $600 million project was constructed by the Sino Hydro company, supported by Chinese state loans. Hide Caption 17 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Fueling development – China has supplied credit worth over $2 billion to an oil refinery project in Angola, although this has been hit with delays. Hide Caption 18 of 19 Photos: Trillion dollar deals: The China-Africa partnership in pictures Road less traveled – The 50-kilometer, eight-lane Thika superhighway was built by Chinese state-owned construction firm Wu Yi in 2012, and supported with Chinese funding. Hide Caption 19 of 19

"Fifty billion dollars a year of construction work is being done by Chinese companies in Africa. There's a huge range," Brautigam says.

Between 2000 and 2011, the Chinese backed more than 1,700 projects in 50 African countries at a cost of $75 billion, according to AidData.

Controversial plans

The Chinese projects are not without controversy, however. Conservationists, for example, have voiced concern that they could disturb wildlife, as they cut through Kenya's national parks.

China has also been criticized for working with undemocratic regimes and bringing their own workers, instead of employing locals.

Conservationists have warned that the megaprojects could disrupt wildlife.

Dreams of a future Cape to Cairo line

New plans could see the network extend even further south. Zambia sealed a deal with China this month which could link up Zambia, Malawi and Mozambique in four years time, according to Zambia's department of transport.

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However, travelers yearning for a trans-African Cape to Cairo railway may be disappointed. New railways are more likely to keep zigzagging from the coastal ports to mines and industrial districts inland, Grantham says.

"There has long been a dream of a Cape to Cairo railway, but the problem is that nobody actually needs to move any goods from Cape to Cairo, so realistically it's not a priority."