Cool for Kids

The Sloping Lock of Ronquières

Any boat-owner will tell you that going through canal locks is a time-consuming process. In the 1960s, the Brussels-Charleroi Canal in particular presented a huge problem, especially around the village of Ronquières in the province of Hainaut. Here, barges bringing coal from the coalfields of Charleroi to Brussels and beyond could waste a whole day navigating 14 locks over a 2 kilometre stretch of the canal with a height difference of 70 metres. And, as they say, money is time. A solution had to be found.

The solution took six years to build and was opened in 1968, and it’s called the Sloping Lock of Ronquières (also called the Inclined Plane of Ronquières).

There’s only one way to describe this incredible feat of engineering …

A giant bath-tub!

I would like you to use your imagination. Think of the bath-tub in your house. And then imagine it being stretched and stretched … to 90 metres long and 12 metres wide and 4 metres deep! Yes, you’re right, that’s a HUGE bath-tub.

Now, fill it with water. It’s going to be heavy, isn’t it: 5000 tons to be precise!

Now what you have to do is imagine a long incline, from the lower level of the canal, extending gradually upwards to the higher level of the canal. The incline stretches over 1.5 kilometres with a height difference of 68 metres.

Are you still with me?

Good. Along this incline you build a 12-metre wide railway track. And you mount the giant bath-tub on wheels and put it on this track.

Then at the top of the incline you make a 5200-ton counterweight, resting on its own set of rails and attached through pulleys and winches and eights set of cables to the bath-tub at the bottom of the incline. And yes, the cables will be 1.5 kilometres long too!


The Giant Bath-tub of Ronquières (official name: the Sloping Lock of Ronquières)

How does it work?

It’s simple. A barge navigates into the bath-tub at the bottom of the incline, the counterweight at the top of the incline is released, and it slowly descends the incline … pulling the bath-tub and barge to the top of the incline at a speed of 1.2 metres per second!

The whole process takes 50 minutes, allowing the barge to sail on its way to its destination.

An incredible invention!

Photos won’t really do it justice. You have to see it in action, so here’s a video. Even if you don’t understand the Dutch or the French, it will give you a good idea of how it works in practice.

Try it out for yourself!

From May to end-August on Sundays you can have a trip on a boat up the Sloping Lock of Ronquières. You can find the details here.

For your Pinteresters, here’s a pin:



47 replies »

    • That’s correct Maggie. Interestingly, apart from the resources needed to construct the thing, it operates pretty environmentally friendly as it’s not powered by a motor. Not bad for the 1960s!

      Liked by 1 person

  1. Wow, Denzil… the trouble they went to to assist. What a feat of imagination as well as engineering. And thank you for the video. That really helped visualise it… and a little refresher of French😍 A lovely post 🌟🌟

    Liked by 1 person

      • You’re welcome Denzil. I’m looking forward to catching up with some of your pieces on your other blog too. Hopefully during the week. As for your question… well, I don’t think we really have them here as far as I have seen. We don’t have the same use for river travel like in Europe. Our Yarra river in Melbourne has canoeists as rafters but not much else. In the centre of the city there are party boats but they mainly do a circuit. Hope that answers your question a little. ‘See’ you again soon 🙋🌟

        Liked by 1 person

  2. This is amazing, I had no idea there were any of these in operation. They created an “inclined plane/caisson” system like this for the Chesapeake & Ohio (the canal that Geo. Washington helped create) in the 19th c., but very surprising to learn of one in use today, and now I’m dying to see it. 🙂

    Liked by 1 person

    • Hi Robert I didn’t know this system was in use elsewhere, but someone else has suggested the design is an old Russian design. I will have to do some research on inclined plane systems. And you’re right, “caisson” is the correct technical term. I just used bath-tub to make it easier to understand! Thanks for your comment.

      Liked by 1 person

  3. Fascinating! One day, I mean to post about the Falkirk Wheel, a rotating boat lift that takes boats from the Forth and Clyde up to the Union canal. It’s more modern than this (post millennium) but is a similarly intriguing feat of engineering.

    Liked by 1 person

  4. This is a wonderful piece of engineering.. I love watching programmes on TV about Canal boat travel, and have visited several large lock complexes in England, that go up in steps through the normal conventional lock gates..
    We am aiming in the future to visit the Falkirk Wheel in Scotland.. This lifts the boat up on rotating device that reconnects two canals..
    I was fascinated watching the film and it made it all the more clearer reading your post and your clear description of it..
    Thank you, I really enjoyed this post Denzil. 🙂

    Liked by 1 person

    • Hi Sue! Interesting: Anabel mentioned the Falkirk wheel in a comment just above yours. It sounds very interesting. I’m glad you enjoyed the post and that you like canal boats. Have you read Narrow Dog to Carcassonne? I loved it, and I hear it was made into a TV programme, but I’ve never seen it. Have you?

      Liked by 1 person

      • Hi Denzil no I have not seen those particular ones but I did follow Prunella Scales and husband Timothy West on a BBC programme.. They followed not on British canals but also went to explore Swedens Gota Canal Very beautiful 🙂


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