Each of the two independent troughs hangs from steel cables 54 millimetres thick, running up over sheaves at the top of the guide towers and down the far side to counterweights. There are 224 heavy-concrete discs per trough, each around 26.5 tonnes, adding up to 5,936 tonnes of ballast for every trough - close enough to the moving weight that the motors are effectively only overcoming friction and trimming the balance. Usable trough dimensions are about 100 metres long, 11.8 metres wide and 3.38 metres deep, and catch ropes at the gates, fitted to stop a vessel running away inside, cost five metres of that length. The vertical travel takes three minutes. Getting a boat right through, gates and manoeuvring included, takes fifteen to twenty.

The lift exists because of the Elbe Lateral Canal, a 115-kilometre cut begun on 6 May 1968 to join the Mittelland Canal near Calberlah to the Elbe at Artlenburg, giving Hamburg an inland route that did not depend on the river itself. Between those two ends lies 61 metres of height. It is taken in two bites: a pair of lock chambers at Uelzen, each 185 metres long, absorb 23 metres of it, and Scharnebeck takes the remaining 38 in a single vertical move, the exact figure varying with the level of the Elbe below. Construction of the lift came to 152 million Deutsche Mark. When it was finished it was the largest ship lift in the world, and the first vessel passed through on 5 December 1975 - half a year before the canal it was built to serve officially opened.

The canal was inaugurated on 15 June 1976 by the federal transport minister Kurt Gscheidle, alongside Hamburg's mayor Hans-Ulrich Klose and Lower Saxony's minister-president Ernst Albrecht. Thirty-three days later, on 18 July, an embankment gave way near Lüneburg. Close to four million cubic metres of water went out across roughly fifteen square kilometres of surrounding country. The lift itself was undamaged and had nothing whatever to do with the failure, but traffic did not resume permanently until June 1977, which meant the machine spent its first two summers as the showpiece of a waterway that had just emptied itself into the fields.

The world record did not survive; Scharnebeck now ranks as the second-highest vertical ship lift in Europe. The more consequential problem is length. The trough takes vessels up to a hundred metres, and modern push-tow convoys are longer than that, which turns a lift built to unblock a waterway into the thing obstructing it. Germany's federal transport plan for 2030 lists the replacement: a lock at Lüneburg with 225 metres of usable length, taking the same 38 metres in one step. When it is built, the twin lift will have been outgrown rather than worn out - a particular and rather dignified kind of engineering fate.

Around half a million people a year come to look, which is a startling figure for a piece of freight infrastructure in the Lower Saxon countryside. There is a museum on site and viewing points on the structure, and the appeal is uncomplicated: very large things moving quietly. The two troughs work independently, so with reasonable luck one descends while the other climbs, and eleven and a half thousand tonnes passes eleven and a half thousand tonnes in mid-air with nothing to hear but cable, gearing and water.