NS invested €898 million in 2018 (€618 million in 2017), for example in New Generation Sprinter trains including a follow-up order, New Generation Intercity trains, the overhaul and modernisation of the VIRM1 trains, and changes to maintenance centres to allow the maintenance of new rolling stock. NS made joint investments with ProRail in the stations of Assen, Rotterdam Alexander and Zaandam, among others. Investments were also made in IT systems for managing rolling stock and staff, and in customer systems, such as the journey planner, aimed at improving the door-to-door journey for passengers, and travelling on account for consumers, with the introduction of NS Flex.