Serbian Prime Minister Aleksandar Vucic and Chinese Minister of Transport of the People's Republic of China Yang Chuantang met at the summit of government officials from China and countries in Central and Eastern Europe.
A statement released Tuesday said that Vucic and Chuantang had agreed on the details of the project including the timetable for research which is to be completed by June 2015, as well as on the means to finance the project and on the date for completing the project which is set for June 2017. Negotiations for the project began on Vucic's visit to the People's Republic of China in September 2014.
The high-speed railway is to run on a double track for rolling stock that can travel at 124 miles per hour (200 kilometers per hour).
"This will put in place a corridor between China and Europe," Chinese Premier Li Keqiang said after the signing ceremony. "With more such express lanes, the scale of our trade will be greater. We are confident we will complete this within two years."
The rail upgrade fits with a Chinese plan to turn Greece's main port of Piraeus -- where Chinese shipping giant Cosco Pacific holds a 35-year concession to upgrade and run two container cargo piers -- into a regional hub for trade with Europe.
Sixteen nations were represented at the summit, including many of the former Yugoslav states, the Baltic countries and EU members Poland, Hungary and the Czech Republic.
The initiative is part of Serbia's plan to become China's gateway to the Balkans and to Europe.
"Our aim is for the feasibility study and all plans to be completed by June next year so that the railway could be built by June 2017," he said.
The summit was initiated three years ago in Budapest, and meetings were held in Warsaw in April 2012 and in Bucharest in November of last year.
China sees the region, comprising some of the EU's newest members and others in the Western Balkans that are trying to join the bloc, as a potentially lucrative market and bridgehead to the wider EU, drawn by relatively low wages, educated workforces and scope for development on the EU's fringes.