Dutch Rail NS  is to invest €502m to upgrade 45 double decker trains, the company said in a statement on Thursday.

The operation will affect 242 individual carriages with a capacity of 24,500 passengers, all of which were built between 2002 and 2005. The refit, which NS terms ‘an investment in comfort, safety and design,’ will be completed in 2021.

This brings NS’s total investment plans for new and upgraded rolling stock to €3bn:  NS has 79 new Intercity and 118 new Sprinter trains already on order.

Refitting train cars is also a sustainable option as most components are recycled and have an estimated lifetime of 20 years, NS said.  The upgraded train cars will have more comfortable seats,  modern lighting and electric charging facilities in both first and second class.