Dutch railway operator ProRail  says more investment is needed on the country’s rail network to absorb the expected 40% growth in passenger numbers by 2030.

If nothing is done, there will be significant capacity problems, particularly in and around Amsterdam and the city’s Schiphol airport, the state owned company warns in an interview with website Nu.nl.

‘We will do okay up to 2030 because we still have growth potential on busy routes,’ design chief Klaas Hofstra said. ‘At the moment we are running six intercity trains an hour between Amsterdam and Utrecht, but that can be increased to eight. But when we get to 2030 we are reaching our limits.’

The capacity limits are partly due to the outdated ATB train security system, which limits traffic to one train every three minutes, Hofstra said. The system was introduced in the Netherlands in 1962 when it was already fairly old and now needs to be replaced.

The European Rail Traffic Management System (ERTMS) allows more trains to use the track and has already been introduced in some sections of the Dutch network.

‘If we want to grow we need new technology but … the budget is insufficient to cover the entire country,’ ProRail safety expert Henri van Houten told the website.

The cabinet has allocated €2bn to introducing the ERTMS system but the European audit office said in 2017 almost €5m would be needed for nationwide coverage.

Other initiatives to boost capacity include doubling the voltage in the overhead cables, which will allow trains to travel faster and introduce automatic train operating systems, which boost efficiency, ProRail said earlier this week.