The Montech water slope is a type of

canal inclined plane An inclined plane is a type of boat lift cable railway used on some canals for raising boats between different water levels. Boats may be conveyed afloat, in caissons, or may be carried in cradles or slings. History Inclined planes have evolv ...

built on the

Canal de Garonne The Garonne Canal (, ) or Canal de Garonne () is a French canal dating from the mid-19th century that connects Toulouse to Castets-en-Dorthe. The remainder of the route to Bordeaux uses the river Garonne. It is the continuation of the Canal du Mid ...

, in the commune of

Montech Montech (; ) is a commune in the Tarn-et-Garonne department in the Occitanie region in southern France. On the Canal de Garonne is the unique Montech water slope, a type of canal inclined plane built in 1974. The slope has been out of service ...

Tarn-et-Garonne Tarn-et-Garonne (; ) is a Departments of France, department in the Occitania (administrative region), Occitania Regions of France, region in Southern France. It is traversed by the rivers Tarn (river), Tarn and Garonne, from which it takes its n ...

, Southwest

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. It is managed by the publicly owned

Voies navigables de France (, VNF, ) is the French navigation authority responsible for the management of the majority of France's inland waterways network and the associated facilities—towpaths, Dock (maritime), commercial and Marina, leisure ports, lock-keeper's houses ...

and by-passes a series of five locks. The slope is used for larger vessels up to 40 metres in length, while smaller boats continue to use the locks. The slope has been out of service since an engine failure in 2009, and was scheduled to reopen in the summer of 2020 but in 2023 was still not working.

Operating principles

The principle of the

water slope A water slope () is a type of canal inclined plane built to carry boats from a canal or river at one elevation up or down to a canal or river at another elevation. History In 1885, German engineer Julius Greve published drafts for water slopes ...

is based on a sloping channel up or down which a wedge of water retained by an (almost) watertight gate is moved. This technique was invented in the 19th century by the German engineer

Julius Greve Julius may refer to: People * Julius (name), a masculine given name and surname (includes a list of people with the name) * Julius (nomen), the name of a Roman family (includes a list of Ancient Romans with the name) ** Julius Caesar (100– ...

and described by the French engineer Jean Aubert in 1961. The Montech water slope was inaugurated in July 1974. An evenly sloping concrete channel is fitted with a gate at the top, around which a continuous trickle of water is allowed to flow, to compensate for any leakage. The lower gate, which can be lifted, is mounted on a yoke between two ex-railway locomotives, which run on concrete tracks either side of the channel. To allow a boat to ascend, the lower gate is lifted, the boat enters the channel, and then the gate is lowered behind it, leaving it floating on an isolated a wedge of water. The locomotives ascend the slope, pushing the water wedge in front of the lower gate. When the water level in the wedge matches that of the upper canal, the upper gate is opened and the boat is allowed to float free. To descend the process is reversed.

Details of the machinery

By virtue of its power and ingenuity the slope's mobile barrier is the key to the system. It consists of: * Two locomotives, rigidly connected together by a cross-piece which spans the channel, with the locomotives travelling on the channel's banks. * The gate, which acts as a big slide-valve, connected to the rigid cross-member by an arm. * A horizontal beam serving as a shock absorber between the boats and the gate. Each diesel electric locomotive has a power of distributed to drive motors on each of the four axles, each with two large pneumatic tyres. The three contact faces of the gate with the channel are equipped with seals to keep the wedge of water in place. The gate is raised or lowered using a hydraulic ram. The shock absorber is a hydraulically levelled hinged metal frame. It allows boats to be connected to the gate during ascents and descents. An electronic system keeps motion gentle and smooth. Finally triple brakes slow the system without jerks.

Design features

* Weight of the engines: 200 tonnes * Pushing effort: 60 tonnes * Speed: 4.5 km/h * Volume of water moved: 1,500 m * Slope of the channel: 3% * Height of the slope: 13.30 m * Depth of water wedge moved: 3.75 m * Length of the water wedge: 125 metres * Power of the locomotives: 2 × * Length of the channel: 443 m * Width of the channel: 6 m * Duration of passage: about 6 minutes * Length, width and capacity of the boats: 38.5 m, 5.5 m and 250 tonnes.

Publicity

The Montech water slope was featured in an episode of the 2005

BBC The British Broadcasting Corporation (BBC) is a British public service broadcaster headquartered at Broadcasting House in London, England. Originally established in 1922 as the British Broadcasting Company, it evolved into its current sta ...

television series ''

Rick Stein Christopher Richard Stein, (born 4 January 1947) is an English celebrity chef, restaurateur, writer and television presenter. Along with business partner (and first wife) Jill Stein, he runs the Stein hotel and restaurant business in the UK. T ...

's French Odyssey.'' Shown as a segment of "Mysteries of the Abandoned" (2018) S2:E7 - Amazon Ghost Town

Science Channel Science Channel (often simply branded as Science; abbreviated to SCI) is an American pay television channel owned by Warner Bros. Discovery. The channel features programming focusing on science related to wilderness survival, engineering, manu ...

Also featured in an episode of "Abandoned Engineering" on the Yesterday channel in the UK (Series 2, episode 6).

Gallery

Montech_pente.jpg, Slope seen from below; movable gate at the top of the slope Montech_arriere_ouvert.jpg, Waiting Montech_fermeture.jpg, Closing the gate Montech_arriere_ferme.jpg, Gate closed Montech_monte.jpg, Boat ascending Montech_cote.jpg, Engines seen from the side Montech_arriere.jpg, Engines seen from below/ from downstream Montech_haut.jpg, Engines and movable gate at the top of the slope

References

External links

*
Canal du Midi
{{coord, 43, 58, 13, N, 1, 13, 39, E, display=title, region:FR_type:landmark_source:dewiki Canal inclined planes Locks of France