My guess would be it is the collision between art and accident.

It looks like maybe they were planning to remove the tails to finish the train line, but before they could someone accidentally wound up on the wrong track.

The train looks empty, so hopefully it was a test of an automatic system that failed and hopefully no one was hurt.

Yikes! I hope it was pure art.

Actually, it burst through the end of the line and only the tails caught it.

"Bij metrostation De Akkers in Spijkenisse is een metro door het stootblok heengereden. Het treinstel bungelt zo'n 8 meter boven de grond en rust op een kunstwerk. Gekeken wordt hoe de metro geborgen kan worden. De metrobestuurder is voor controle naar het ziekenhuis gebracht."

Very... very.... carefully.

The sculpture is actually NAMED "Saved By a Whale’s Tail"?!

The artist is a prophet!!