A court case opens on Tuesday to determine if the makers of an electric wagon used by daycare centres to transport children are responsible for the death of four of them in a crash with a train.

Families have been preparing for this moment “for a very long time”, said Lars Walder of the foundation Namens de Familie, which has supported relatives of the children throughout the process.

The accident happened on September 20, 2018, when a childcare worker was taking children to school in a Stint motorised carrier but failed to stop at a level crossing.

She later told investigators she had been unable to brake, though no precise cause was ever established. The vehicle was struck by a train, killing four children and seriously injuring their carer and another child.

Two companies and two managers responsible for producing and selling the Stint now face trial. Investigations in recent years found multiple technical defects in the vehicle, including inadequate brakes, a faulty throttle, no start-up protection and no way to carry out an emergency stop.

The public prosecution department says the managers were aware of these issues and chose not to disclose them. Expert reports, exchanges with customers, recorded phone calls and witness statements all point in that direction, the department said.

The case is starting years later than expected because the initial investigation focused mainly on the accident itself. In 2020 the prosecution department finally said the care worker had done everything possible to prevent the crash and should not face charges.

The wagons were allowed back on the roads after tougher safety checks and new regulations including seat belts for the children and better breaking.