Kenya has launched a $13.8bn flagship railway project linking the port city of Mombasa to the capital Nairobi and is eventually hoped to extend onwards to neighbouring Uganda.
The project, called a "historic milestone" by President Uhuru Kenyatta, who presided over a ground-breaking in Mombasa on Thursday, will also connect with proposed lines to Rwanda and South Sudan, according to the AFP news agency.
Kenya is stepping forward...it will be a landmark project both for Kenya and east Africa.
Built by a Chinese state-owned firm and with funds from the Chinese government, the railway line is expected to dramatically increase trade and boost Kenya's position as a regional economic powerhouse.
Kenya, Uganda, Tanzania, Rwanda and Burundi form the the East African Community, a regional bloc that the five nations have used to boost economic integration.
"What we are doing here today will most definitely transform... not only Kenya but the whole eastern African region," Kenyatta told crowds at the ceremony, which was attended by Chinese officials.
"As a result east Africa will become a competitive investment destination. A busy growing east Africa is good for us as a country."
The new railway line will replace the dilapidated British colonial-era railway, and has been hailed by the Kenyan media as the region's largest infrastructure project for a century.
"Kenya is stepping forward...it will be a landmark project both for Kenya and east Africa," said Liu Guangyuan, China's ambassador to Kenya.
Financing, currently only from China, has so far been made for only the first 450km section from Mombasa to Nairobi, replacing the current single trainline with a high-speed standard gauge track, as well as building an additional line alongside.
Work on that section, by the China Road and Bridge Corporation (CRBC), is expected to be completed by 2017.
CRBC completed in August the first-stage of an expansion to Mombasa's port, including a berth able to handle 50,000 tonne container ships
According to plans, the new lines would see passenger journey times cut from the current 12 hours to around four, which is around half the current driving time on crowded and pot-holed roads.
Freight trains are planned to be able to cut the current 36-hour trip by rail to just eight, a major boost for regional landlocked nations, with planners claiming it will slash cargo transport costs by 60 percent.