This unique construction makes it possible to compensate for a difference of 73 meters in level and replaces the four hydraulic lifts (Unesco World Heritage Monuments) and two locks of the famous historic Centre Canal.
The canal now provides a direct link between the busy inland waterways of the basins of the Escaut/Schelde and the Maas/Meuse, thanks to the three nearby technological achievements setting new world records: the highest lift-lock, at Strépy-Thieu, the most massive extruded concrete bridge, at Pont du Sart, and the giant stop-lock at Blanc-Pain.
On this picture you see the importance of the level difference between the lower and the upper part of the canal. Behind the building you can already see the most massive extruded concrete bridge which continues into the canal bridge.
The view has been taken from the old Center canal.
A few figures about the funicular lift : 2 tubs, 119 by 17 meters wide and weighing about 8.000 tons, each suspended by 144 cables 81/2 cm in diameter. The size of the roof of the lift is equivalent to a football field.
It is also part of the Unesco World Heritage monuments.
How does it work ?
These lift-locks consists of a pair of tanks, each as large as a conventional lock chamber and closed at each end by a "guillotine" gate. The adjacent ends of the upper and lower pounds of the canal are fitted with similar guillotine gates such that when the tank is clamped to either of them, which seals the sides and bottom of the gap between the gates, and the water levels in the tank and gap have been equalised with that in the pound, the gates can be raised together. Each tank is supported by a central column which acts like a piston in a deep vertical cylinder filled with water at high pressure, linked with that under the other column through a pipe with a valve that can be opened and closed as required. The total volume of water at high pressure is kept constant at the quantity needed to ensure that when the lower tank is correctly aligned for opening the gates from the lower pound, then the upper tank is similarly at just the right height for opening the gates from the upper pound.
As the total volume of water displaced by any vessel entering the tank has exactly the same mass as that vessel, the two tanks remain in equilibrium so long as the depth of water in them is the same. Once the tanks have been loaded, the gates are dropped, the clamps released and enough water to reduce the surface level by about 30 cm is let out from the lower tank into the pit underneath (from which it drains away through a pipe laid beneath the lower pound). When the valve in the connecting pipe is opened, the unbalance is sufficient to make the upper tank descend to the lower level, thus raising the other tank to the position where it can be clamped to the upper pound; the valve is then closed. As the water level in the upper tank is now about 30 cm below that in the upper pound, water must be allowed to flow from it into this tank until the levels are equal. Then the guillotine gates can be opened and the cycle repeated.
The first hydraulic lifts was built between 1880 and 1888. The other three became operational in 1918. They are now Unesco World Heritage Monuments and the only ones still working all over the world.
Next to hydraulic lift nr. 3 the machinery rooms are open to visitors between 9 a.m. and 5 p.m.
The hydraulic lifts which are listed as World Heritage by Unesco are the only ones still working in the world
The village of StrépyBracquegnies is enclaved between the new Canal du Centre (in front) and the initial one (behind)