The Reunification Express (Tuyến Dýờng sắt Thống Nhất) is Vietnam's principal railway service, stretching 1,726 kilometres from the political capital of Hanoi, to the commercial centre of Ho Chi Minh City down south. The single narrow one metre wide gauge track serves as a vital lifeline between the two cities and the towns in between.

The track itself was built over time by the French colonialists from 1899, with both ends of the Transindochinois joining up in 1936. Time enough to be used by the Japanese in the Second World War. Services between the two cities were suspended at the outbreak of the civil war in 1954. During the Vietnam War the northern lines were bombed by the Americans while the Viet Cong sabotaged the southern lines. The Reunification Express trains went back into service in 1976, after 1334 bridges, 27 tunnels, 158 stations and 1370 shunts had been repaired.

Starting in Ho Chi Minh City, the track meanders no more than 100kms from the coast, stopping at Vinh, Hue, Danang, Quang Ngai, Nha Trang, Thap Chan and other towns. There are four services a day, with the trains departing Hanoi and Ho Chi Minh City simultaneously at: 12:30pm (S4/S6 express, 40 hours), 3:40pm (S3/S4 express, 40 hours), 7:00pm (S1/S2 express, 33 hours 30 minutes) and 11:00pm (E1/2 express, 30 hours 30 minutes). Trains maintain an average speed of around 50km/hr, pulled along by locomotives built in the former Czechoslovakia.

Fares are calculated according to a complicated formula that the Vietnam Railways website struggles to load (www.vr.com.vn). There are hard seats, soft seats, hard berths and soft berths, and the prices vary again depending on the number of intermediate stops, the presence of air conditioning, the number of berths in a cabin and even which bunk layer the passenger sleeps in (the top bunks are the cheaper). To travel the entire arduous journey on a hard seat would set you back 380,000 Vietnamese dong, while the bottom bunk in a four berth air conditioned cabin costs 846,000 Vietnamese dong (about US$35 and US$77 respectively). Until 2001, foreigners and Viet Kieu had to pay according to a higher fare schedule.

In Hanoi, it is possible to change to a Beijing-bound train, and in turn end up in Aberdeen by changing trains in Moscow, Brussels and London.