brake pads were causing the wheels to wear unevenly and too quickly. The maintenance schedule of the trains was adjusted, and real-time monitor systems were added to determine if the trains require extra or earlier maintenance. The trains are expected to be slowly phased back into regular use beginning on December 6, 2021. Reactivation In November 2013, NS decided to reactivate the remaining DDARs. Due to problems concerning the HSL, there would have been a shortage of trains. Thus, 19 new compositions of DDAR-coaches were formed, consisting of 3 coaches and a 1700 locomotive. The first of which entered service in December 2014. Each of the 19 compositions received minor refurbishments in Haarlem. Services operated The DDZs are regularly used on these services in the current timetable (2018). They can sometimes appear on other services. Details References Electric multiple units of the Netherlands Waggonfabrik Talbot Double-decker EMUs 1500 V DC multiple units of the Netherlands