The incident occurred on Tuesday at approximately 3:25 a.m. (0:25 GMT), while the Leiden to The Hague night train was passing through the nearby municipality of Voorschoten.
Pictures taken at the site showed one carriage having slammed into a field and another lying tilted on the track. A spokesperson for the emergency services reported that a small fire had started in the back carriage but had been swiftly put out.
The train was transporting about 50 passengers, 30 of whom sustained injuries, according to Dutch Railways (NS). Some required treatment for minor injuries at the scene, although 19 were taken to various hospitals, including a facility opened in the central city of Utrecht in response to the emergency.
There was initial speculation that the crash was caused by a collision with a freight train. However, a regional emergency response body later suggested that a small construction crane may have been left on the track.
The piece of equipment was reportedly found at the crash site but its role in the tragedy is yet to be established conclusively.
John Voppen, CEO of the ProRail network, called the accident “a black day for Dutch railways” and said his thoughts were with everyone affected. Voorschoten Mayor Nadine Stemerdink described the incident as “incredibly tragic” and offered her condolences.
NS stated on Twitter that no trains would be running between Leiden and The Hague due to the accident.