The CRH380A has a maximum speed of 486 kilometers per hour. The 25-minute trip took the leaders from the garden city of Suzhou to financial hub of Shanghai, 100 kilometers away, speeding past industrial parks and factories much of where laid bare farmlands just a decade ago.
At that speed, the train would take less than 20 hours to travel from Beijing to any of the leaders' hometowns.
Flags of China and 16 CEE countries and slogans that read "16+1>17" were painted on the body of the 16-carriage train, highlighting cooperation and development between China and the 16 countries which just completed an annual summit meeting in Suzhou, east China.
"The trip mirrors China-CEE cooperation - high speed, but comfortable and reassuring," Li told the European leaders.
"It is very impressive," said Hungarian Prime Minister Orban Viktor. "China's development is indeed admirable."
His words echoed those of Polish President Andrzej Duda who said a day earlier that he hoped Poland and the entire Central and Eastern Europe could all benefit from China's growth.
Estonian Prime Minister Taavi Roivas expressed hopes that China will take part in high-speed railway construction in the Baltic region.
ALL ABOARD
Wednesday's excursion came just a day after China signed two separate deals with Hungary and Serbia on a high-speed rail link between Budapest and Belgrade that could cut travel time between the two capitals from eight hours to less than three.
Once completed, the railway will become part of a fast lane for importing and exporting goods between China and Europe. Macedonia also inked a deal with China in June to purchase six fleets of high-speed trains.
China is actively working to export high-speed rail technology, with domestic and foreign media sometimes referring to Premier Li as the country's top railway salesman. A new term -- high-speed railway diplomacy -- has entered Chinese political parlance.
The situation is clearly win-win. China gets to upgrade its economy and partner countries get infrastructure with lower costs.
China's first overseas high-speed rail project was completed in Turkey in 2014 where a 533-km railway links capital Ankara with Istanbul. In Africa, China's technology will be the backbone of the public transport systems in countries including Nigeria and Ethiopia.
A 1,344-km railroad went into operation in Angola in 2014 and last May a deal was struck to build a 3.8 billion dollar line between the two Kenyan cities of Mombasa and Nairobi, the first phase of a line that will eventually connect Kenya to Uganda, Rwanda, Burundi and South Sudan.
In September, Malaysia began running the world's fastest meter-gauge multiple unit trains made by Chinese. Laos, Thailand and Russia also plan high-speed railway lines with Chinese investment.
In South America, Chinese trains began ferrying Buenos Aires' commuters to work last November.
High-speed rail in Central and Eastern Europe is a new idea, but the long-term effects are not difficult to assess. With China's ambitious plans taking shape, Central and Eastern Europe will soon have a new, convenient channel to import and export products to and from Asia.