Russian President Vladimir Putin opened the railway linking the Crimea to Russia on Monday, in a move that poses a new challenge for Ukraine, after Moscow annexed the peninsula in 2014.
"It is a delightful and very important event for the Crimea (...) and for southern Russia and our entire country," Putin said at the opening ceremony.
The line is located on the bridge linking the Kerch Peninsula in Crimea to Taman Mountain in southern Russia, where Putin previously made the first crossing in the cockpit alongside the driver along the 19 km.
The road section of the bridge was opened in May 2018. Putin then crossed as he was driving an orange truck advancing a motorcade of about a dozen vehicles.
The project was launched in February 2016 and entrusted billionaire Arkady Rothenberg, Putin´s partner in the judo game.
Trains connecting Moscow and St. Petersburg to Simferopol, the Crimean capital, are expected to carry 14 million passengers in 2020.
The first train left Saint Petersburg on Monday, with a journey time of 26 hours.
Russia annexed the Ukrainian Crimea in March 2014 after a referendum denounced by Kiev and the West.
This annexation was followed by an armed conflict between Ukrainian forces and pro-Russian separatists in eastern Ukraine, and this ongoing conflict resulted in the deaths of more than 13,000 people.
