It is one minute to 7pm at the main railway station in central Hanoi. The relaxed bustle of boarding is complete, and a palpable air of expectation hangs over platform 1. An electric bell rings, the locomotive hoots impatiently. Outside each carriage door, a uniformed attendant looks nervously up and down the train, holding a lantern aloft and waiting for the off.
From the station loudspeakers, a last urgent call in staccato Vietnamese fills the warm night air. As the second hand sweeps towards the 12, the attendants step smartly up into the train, removing the numbers hung outside their carriage doors. One long blast and one short toot on the horn, a muted hiss from the brakes, and train SE1 glides gently off into the night on its 33-hour, 1,070-mile journey to Vietnam's second city, Ho Chi Minh City (Saigon).
This is the celebrated "Reunification Railway", a steel artery running the length of Vietnam. It was completed in 1936 in what was then French Indo-China, and its trains ran for 18 short years before the French pulled out and the country split into North and South. Hanoi station is still visibly a French colonial building, despite its stark concrete central section, an ugly reminder of a direct hit by American bomb in December 1972.
Not until 1976 did the north-south trains resume, and four or five air-conditioned trains now link Hanoi, Vinh, Hué, Da Nang, Nha Trang and Saigon every day, providing affordable and relatively comfortable transport for locals and visitors alike.
I had last visited Vietnam more than a decade before, and as the SE1 raced the frenetic road traffic through the Hanoi suburbs, it seemed that every cyclist then now owned a motorbike, and every motorcyclist a car. Tourism has also boomed, and I was travelling in one of two privately run Livitrans sleeping-cars aimed at visitors, a cut above the SE1's regular "soft sleepers" but still only $59 (£38) for the 494 miles to Da Nang.