The Reunification Express, known as the Thong Nhat Railway, traverses more than 1,726 kilometers (1,072 miles) between Hanoi and Saigon, the country’s two biggest cities, in two days.

"There is no more atmospheric way to haul into Vietnam’s twin metropolises. And there’s no better way of exploring all the glories in between," Lonely Planet said.

The journey allows passengers to sit and enjoy romantic scenery and rural landscapes along coastal towns in the central region including the former imperial capital of Hue, the Da Nang City Port which was initially built in the French colonial time and the ancient town of Hoi An.

An aerial view of Hue Imperial Citadel, a major tourist attraction
in the ancient capital Hue, central Vietnam. Photo by Shutterstock/anhuy.

The other train journeys Lonely Planet lists are the California Zephyr in the U.S., Baikal–Amur Mainline in Russia, China’s Beijing to Lhasa Express, and the TranzAlpine in New Zealand.

The north-south rail has been deteriorating after decades of use since being built by the French in the 1930s. Rail transport is rapidly losing popularity given the rise of cheap air travel.

Vietnam’s aviation industry has been growing at the third fastest pace in the Asia-Pacific, according to the International Air Transport Association.

The railways carried 9.4 million passengers last year, down 3.5 percent from 2017, according to government data.

Some companies have been trying to revive the romance of train travel, offering first-class trips with attached restaurant cars like the five-star services launched in 2017 from Saigon to the coastal resort town of Nha Trang and from Hanoi to the northern highlands town of Sa Pa.

Russian news agency Sputnik recently included the north-south rail among world’s 10 most beautiful.

Last year travel publisher Rough Guides named it as one of the most scenic in Asia, where one can watch buffalos grazing in rice paddies, fishermen casting their nets in the sea, deserted white beaches, and lush rainforests.