Cuba's first new train passenger cars in more than four decades set off on Saturday in what the government hopes will prove a total revamp of its decrepit railway system with help from Russia and China.

Cuba's railway system is one of the oldest in the world; its first stretch was launched in the 1830s. But it has suffered from a lack of maintenance and new equipment in an inefficient state-run economy under a crippling US trade embargo that lacks cash.

Trains have for years been one of the cheapest but also least efficient ways to travel long distances on the Caribbean's largest island, typically taking 24 hours to cross the nearly 900 kilometers from Havana in the west to Santiago in the east - twice as long as by car.

Tickets are often elusive, with the ramshackle infrastructure unable to cope with the demand, and trains do not run on schedule. Passengers, meanwhile, must contend with missing windows and doors, and cracked seats. Accidents have become increasingly common in recent years.

But Cuba's government is planning to change all that by 2030, starting with upgrading its equipment, before moving onto the more daunting task of restoring the railroads.

In May, it received some Chinese-made, gleaming blue rail cars, including those that set off eastward from Havana on Saturday, and expects to receive more next year, according to state-run website Cuba debate.

"This is the first step of the transformation of the Cuban railway system," said Eduardo Hernandez, head of the National Railway Co of Cuba.

Reflecting market reforms of the  country, the new rail cars are split into first and second class, with the former boasting air conditioning.

"Cuba has not received new rail-cars since the 1970s," Transport Minister Eduardo Rodriguez was quoted as saying by Cuba debate last month. "We had only received secondhand cars."

While the new trains are expected to shave off some traveling time, they will require new or restored track to run at their full speed.

Cuba has signed a deal worth almost $1 billion with Russia to modernize its railways, according to Interfax news agency, although details have not yet been released.

In 2017, state-owned Russian Railways (RZD) told Reuters it was also negotiating to install a high-speed link between Havana and the beach resort of Varadero.