Although it takes more than a full day for the existing North-South Railway to cover the 1,726 kilometers between Hanoi and Ho Chi Minh City, the line is still much beloved by local people.

The rail link, which survived U.S. bombing in the Vietnam War, has become a symbol of the country's healing brought about by unification.

At 7 p.m. on May 8, a 13-car train, pulled by a China-made "D19E" locomotive, began to chug out of Hanoi Station. Images of Japanese "Hinomaru" national flags and cherry blossoms adorned the passenger carriages.

It was the first of a series of trains that are scheduled to run on the line until Sept. 23 to commemorate the 40th anniversary of diplomatic relations between Japan and Vietnam.

The first train was expected to arrive at the terminal, Saigon Station, at 4:10 a.m. on May 10, after a 33-hour journey.

A one-way first-class ticket costs 1.845 million dong (about 9,000 yen, or $90). That provides the passenger with a bunk in an air-conditioned sleeper compartment that can accommodate four people. The fare is almost the same as for a flight between the two cities.

A ticket for a bunk in a sleeper compartment without air conditioning costs 1.342 million dong. Passengers willing to nap on wooden seats need pay only 728,000 dong.

Because most of the train cars are more than 10 years old, window frames and metal fittings for the bunks are rusty. However, the toilets and wash stands are well-maintained, and clean sheets are provided.

Although all of the passenger cars were air-conditioned, the equipment was not functioning properly in some of them, prompting passengers to try to stay cool with paper fans.

Some male passengers removed their shirts and huddled in the flexible gangway connection between carriages, where it was drafty.

At 8:39 p.m. on May 8, the train pulled in to Nam Dinh Station, about 70 kilometers southeast of Hanoi. Nam Dinh is a satellite city of the capital.

Waving Hinomaru flags, students of a Japanese school there welcomed the train.

After leaving the station, the lights of running motorcycles and buildings along the railroad gradually gave way to rural scenes and sleepy agricultural communities.

An elderly woman began to put on pajamas she had brought with her. A man, clearly a factory worker, slouched over two seats. A middle-aged woman threw herself on the floor by spreading a straw mat.

"Rich people use airplanes. But we use this railway, even though it takes much longer," said a 20-year-old university student, who gave his name as Thang. Then, he leaned on the back of his seat and positioned a small backpack in his arms.

Immediately before the train arrived at Dong Hoi Station, at 5 a.m. on May 9, an announcement, which sounded like a traditional Vietnamese ballad, blared out. It was a wake-up call.

Brownish-red tile-roofed farmers' houses and green rice fields glistened in the morning sun.

After leaving the station, the train slowed as it approached a bridge that was being repaired.

"We are repairing that bridge," said Yoshitaka Komuro, 55, director of the Hanoi representative office of Japanese construction company Tekken Corp., who was traveling in the same compartment.

Construction of the North-South Railway began in 1899. Trains didn't start running on the line until 1936, however.

During the Vietnam War, many bridges on the railway were blown up. The line was restored in 1976. Because of that, the railway came to be known as the symbol of unification for North and South Vietnam.

Engineers, funded by Japanese government yen-loan programs, have fixed aging track and many of the bridges.

Repair work has been undertaken in 63 places, and completed in 29 of them.

Bridges that were antiquated or in such a poor state of repair that trains had to reduce speed were replaced. As a result, the travel time between Vietnam's two major cities was slashed from more than 70 hours to around 30 hours now, when conditions are perfect. There are plans to slice six more hours off the travel time.

According to Komuro, the replacement of bridges is an intricate operation. It involves erecting a bridge next to the one to be demolished, and then nudging it into place.

The final stage of a bridge replacement requires about 80 engineers from both Japan and Vietnam working together. The task usually takes about four hours.

At 10:10 a.m. on May 9, the train passed through the scenic Hai Van Pass, which served as a stronghold for French, U.S. and Japanese forces during World War II as they tried to track enemy positions.

The pass possesses a commanding view of the turquoise South China Sea. The train arrived at the pass 30 minutes behind schedule. However, a train employee said, "There are no problems."

A woman from France, heaving a bulky backpack, said cheerfully: "This train has a unique atmosphere, which is different from those of trains in any other countries. I am so excited."

In northern Vietnam, the sky has a darkish hue. But as the train entered the central region, the sky took on a brighter aspect.

After the train negotiated mountain slopes, Da Nang, the commercial hub of the country's central provinces, came into view.

Carts stacked with lunch boxes, yoghurt and other types of food moved up and down the train. Passengers can choose side dishes of grilled chicken or fish. A lunch box with rice was priced at 40,000 dong. Yoghurt was 10,000 dong.

Stalls selling bananas or rice wrapped in leaves, like "chimaki" (rice dumplings wrapped in bamboo leaves), were positioned in front of stations.

It was tempting to leave the train to make a purchase. But the stops at each station are only for five minutes. The smart option seemed to be to stay on board.

Thus, the dining car beckoned. Rice noodles, called "pho" and a Vietnamese specialty, had already sold out. Wheat noodles, called "mi," were available, however. They were priced at 30,000 dong.

The train trundled southward through areas of rice fields. The scenes that passed by reminded me of Japanese agricultural villages. But something was different: There were no tractors, only water buffaloes pulling hoes. Farmers harvesting rice wore sedge hats.

The sun began to go down.

Soon after 9 p.m., a ballad sounded on the intercom to encourage passengers to get some shut-eye.

A Vietnamese family who had been in my compartment from Nha Trang, known as a beach resort, were on their way home in Ho Chi Minh City after spending their holidays at relative's house near the beach.

At 4:05 a.m. on May 10, the train arrived at Saigon Station in Ho Chi Minh City. Through the window, I could make out buildings of the country's largest city, even though it was still dark. The train, which had made up for a delay, arrived at the terminal five minutes earlier than scheduled.

"As I told you, there are no problems," the rail employee said proudly.

In 2010, the Vietnamese Cabinet gave the go-ahead to introduce Japanese Shinkansen bullet trains. But the decision had its detractors, because of the huge cost, estimated in excess of 5 trillion yen. The decision remained in limbo, pending parliamentary approval.

Then in March this year, Transport Minister Dinh La Thang said, "Our country is still poor." The remark spelled the death knell for the project for the time being.

Tran Quoc Dong, deputy general director of the Vietnam Railway Corp., told The Asahi Shimbun, "The Shinkansen is attractive. But, first of all, we want to make efforts to improve the systems and services of the existing (North-South) railway."

The state-run railway operator aims to introduce Japanese technologies in the fields of communications and safety.

"It cannot be said that faster is better. There is also a way of enjoying a trip by boarding a train at night and arriving at the destination in the morning," he said.

By Manabu Sasaki - The Asahi Shimbun - June 27, 2013