Incredible footage captured a runaway train being saved by the sculpture of a Blue Whale’s tail in the Dutch suburb of Rotterdam, yesterday.
The story of the unique specialist Dutch engineering that went into the whale’s tail turns out to be equally compelling, especially with the skin of the whale being made of hollow plastic that was only only 6 mm thick.
19 years ago, Hans Muller, Peter Globevnik, and Eric van Uden completed the ‘Whale Tails’ sculpture that sits at the end of the metro line in Spijkenisse, a suburb of Rotterdam in the Netherlands. At the time, they used a pioneering engineering technique with a novel material – all of which was cutting edge for the time.
Yesterday, they were shocked to see a metro train sitting on top of one of those whale tails.
“My first thought when I saw the photos was this can’t be true! This tail was not designed for this,” said Muller.
“I thought it was an impressive sight to see that the whale tail was holding the whole carriage in the air. The driver was very lucky to get out of there safely! I’m happy he is safe,” added van Uden.
It becomes even more incredible when it turns out the tail of the whale is only 6 mm thick, and was able to hold up a 20 ton train engine almost two decades after construction. This was all achieved using what was then a cutting edge advanced manufacturing technique, which relied upon composite engineering, specialized materials and predictive modelling. The secret lay in both the design and construction of this new composite plastic material that was both lightweight and incredibly strong at the same time.
Hans Muller has a background in naval architecture and founded Solico Engineering in 1989. Today, it is the largest composite engineering company in the Netherlands.
Peter and Eric joined Hans three years later. Solico specializes in composite engineering and advanced manufacturing for bespoke projects in defense, maritime, architecture, automotive and other niche manufacturing and industrial sectors.
Although Solico are not currently working on any other sea creature related sculptures at the moment, they have ongoing projects in the maritime industry such as tidal turbines and composite parts for yachts.
Whale tails designed for Rotterdam’s winds
The whale tails were originally engineered to solve a different issue, the strong Dutch winds typical in the coastal town of Rotterdam.
“The shape of the fluke on the whale tail makes a perfect wing. We knew that this could get a lot of lift force with the wind which presented us with an engineering challenge,” explained Globevnik, the head structural engineer behind the tails. Also getting the Eigen Frequency right, led to a very strong structure. Fortunately, the stiff and strong structure of the tail was able to catch the metro train.
The Eigen Frequency is the natural state of vibration of a structure, and if incorrectly calculated could lead to that structure’s collapse. One of the most famous examples of the importance of the Eigen Frequency is the collapse of the Tacoma Narrows Bridge in the US State of Washington in 1940, after only four months of operations and 40 mph winds. At the time of its collapse, it was the world’s third longest suspension bridge.
Tacoma Narrows Bridge collapse, USA (1940)
Whale tails sculpture chosen by local citizens
The inspiration for the whale tails came from the citizens of Spijknesse who wanted an artwork to mark the ‘tail’ of the track of the newly completed transport line.
According to Muller “The people who lived there said, if this is the end or tail of the track and the end of a fish is called a tail, then we should have tails at the end of this track.” Initially, the concept involved using fish tails of herring – a local Dutch favorite. Fortunately, an alternative design was chosen as it is unclear whether a herring’s tail could have held up the weight of the runaway train.
The Rotterdam city architect liked the idea of a fish tail and eventually came up with a mockup of two whale tails. They were both Blue Whale tails and were designed to the actual scale of adult Blue Whales whose tails would be 12 meters long. The official name for the sculpture is ‘Saved by the Whale’s Tail’ which seems particularly prophetic given the overshooting train.
Maarten Struijs, the Rotterdam city architect who was in charge of the design has expressed astonishment that a structure made of plastic happened to not only have stopped a runaway train in its tracks but also to have held the weight sustainably preventing the train carriage to fall 30 feet onto a bicycle path directly underneath.
In an interview with the Dutch broadcasting corporation (NOS), Maarten Struijs exclaimed that he felt that the event was a “miracle.”
While there is certainly an element of luck in the whole incident, this miracle can also be explained by how art, science and engineering came together to lead to this unlikely yet amazing outcome.
The tale behind the whale save
In order to build a strong, sustainable structure, Hans Muller, Founder of Solico, enlisted the help of an experienced biology artist specialized in creating composite sculptures for zoos.
Together, the architect, the biology artist and the engineers worked on a model where the design of the tails would follow nature’s proportions and the implementation would require one of the earliest uses of industrial scale 3D printing. The 3D printed designs allowed the engineers to test the resilience of the sculpture in wind tunnels.
Rotterdam experiences a lot of strong winds that have resulted in vibration issues with other nearby projects.
Solico’s Head Engineer, Globevnik, and CEO Muller, went to a wind tunnel with the 3D printed scale models in order to test them for vortexes, lift and air circulation.
“We were surrounded by people from Airbus and offshore companies and here was Solico with two whale tails. A strange sight indeed,” said Muller.
Solico used the data obtained from the wind tunnel experiments to engineer a much stronger and stiffer composite material design for the whale tails.
They used advanced mathematical techniques to digitally model the effects on the physical structure. This advanced technique, called Finite Element Analysis, allowed significantly fewer physical prototypes to be built and relied on advanced mathematical models of fluid dynamics, wave propagation and thermal analysis.
It was this combination of these advanced mathematical models, the 3D printing to allow for wind tunnel testing, as well as the cutting edge additive composite material innovation, that has allowed the whales tails to be so robust and much more than just an art sculpture.
Once the designs were set, Solico teamed with Maropol, a production company specialized in custom applications of moldings, to create the final sculpture.
They created one tail as a steel ladder structure covered by a composite skin while the other is a hollow composite plastic structure without a steel structure.
It was actually the latter without the steel structure, that ended up being strong enough to withstand the impact of and support the carriage of the runaway metro train.
The skin of the structure is only 6 mm thick. It shows the incredible engineering that had been put in place to ensure the reinforced polyester fiberglass could hold up a 20 ton train engine.
The techniques pioneered with the whale sculptures have allowed a variety of new industrial applications to be built two decades later.
Solico is now a firm of four partners, with Doenan Mager recently being elected, and continues to push the frontiers of advanced manufacturing. They are involved in the designs of large scale tidal and wind turbines, as well as ship propellers of the future, among other advanced industrial applications.
Finally, a good use of plastics for marine life
Environmental groups have long lamented how plastics are impacting marine life in our oceans. Indeed, greater action is certainly needed to prevent there being more plastics than fish in our oceans by 2050.
But in the Dutch suburb of Spijkenisse tonight, there is at least one train driver grateful that the plastics had not been removed from this whale’s tail.