Work is due to start in the middle of this year, and the refurbished trains will re-enter traffic between 2014 and 2016. NS says the programme covers the refurbishment of 416 vehicles.

The VIRMs were originally delivered to NS as three and four-car sets but were subsequently extended to four and six-car formations. Today NS operates a fleet of 80 six-car and 98 four-car VIRMs, which were delivered over a 15-year period.

Apart from work to improve their technical condition, the trains will be upgraded with new interiors similar to those on the New Intercity Double-decker (NDD) vehicles, which were converted from DD/AR regional double-deck stock.

Moreover the refurbishment will have to meet NS' policy for sustainability, with a 20% reduction in energy consumption. The trains will therefore be equipped with an energy efficient climate control system and LED lighting.

All refurbishment works will be carried out by NS' train maintenance and refurbishment subsidiary Nedtrain at its workshops in Haarlem.