The maintenance work was planned and standard, but “we have no idea how the crane got on the track which was still open for traffic”, John Voppen, the CEO of railway infrastructure firm ProRail, said at a news briefing.

Rescue teams ferried away the injured in pre-dawn darkness at the scene of the incident in Voorschoten, a village near The Hague. The accident happened around 3:25 a.m. (0125 GMT), emergency services said.

Some of the injured were treated on the spot and 19 were taken to hospital.

Train services will be suspended for days between The Hague and Leiden, one of the busiest routes in the Netherlands, ProRail said.The crane was part of maintenance work on two tracks which were closed for traffic, while two other of the total of four tracks remained open for train traffic,” ProRail’s Voppen said.

Dutch construction group BAM told newspaper NRC and ANP news agency that it was one of their employees that died in the accident. It did not immediately respond to a request for comment.

The driver of the passenger train is in hospital with bone fractures, Dutch railways NS CEO Wouter Koolmees said at the news conference.

The front carriage of the night train from Leiden city to The Hague derailed and ploughed into a field, emergency services said. The second carriage was on its side. A fire broke out near the train but was soon extinguished.