China Railway Construction Corp. Ltd. (CRCC) signed the official construction contract with the Nigerian government on Wednesday in Abuja, the Xinhua news agency said.
The Nigerian railway will stretch for 1,402 kilometres (871 miles) along the coast, linking Lagos, the financial capital of Africa's largest economy and leading oil producer, and Calabar in the east, according to the report.
The $11.97 billion deal marks China's largest single overseas contract project so far, it said, citing CRCC.
The news came two weeks after Mexico cancelled a $3.75 billion bullet train deal only days after it was signed with a Chinese-led consortium headed by CRCC - the sole bidder - reportedly due to concerns about transparency.