The NS Class 3400 was a series of diesel multiple unit which were in service in the Netherlands between 1996 and 2017 and were built by Duewag, Talbot and SIG between 1996 and 1998. They were operated by the Nederlandse Spoorwegen and between 1999 until 2014 under lease by Syntus. The class is referred to as DM'90 meaning diesel rolling stock (Diesel Materieel in Dutch) of the 1990s or Buffel, which means Buffalo. The DM'90 series was developed alongside the short lived, electric SM'90 ("stopping-train" or commuter rolling stock of the 1990s) series with which it shares the unusual body cross section. Class 3400 were the last DMUs in service with NS, the older DE3 ("Plan U") and DH1/2 ("Wadloper") series having been replaced by the diesel electric Stadler GTW which are still in use with other operators in the Netherlands. Since January 2018, all units are now stored out of service and 32 units have been sold to SKPL - Polish private railway operator. History In 1993, NS ordered 53 units of the class from Talbot, now Bombardier. The electrical systems, train controls, and diagnostic systems were delivered by Holec Ridderkerk, now Alstom. Duewag installed the interiors of the trains in Krefeld, after which the units were transferred to the Netherlands. Unit 3401 was delivered on March 12, 1996, and the last unit, 3453, was brought into service in 1998. Originally there were intentions to order a follow-up series of the 2-car units, alongside the possible development of a single-car unit, however these were never realised due to the privatisation of many of the diesel-served lines. The rolling stock was introduced in the end of the 1990s on a large portion of the non-electrified lines in the Netherlands. In the period thereafter many of these routes were transferred to private sector operators, Syntus and several other operators used the sets for their services, others were temporarily used on electrified sectors for local services. Description Like the SM'90 ("Railhopper"), the DM'90 uses a non-standard width of , this was made possible by the distinctly bent side-walls which allowed the cars to be wider than conventional trains while being within the loading gauge. This allowed a 5 abreast seating arrangement, however the trains were eventually delivered with only the standard 4 abreast configuration. Power is provided by two Cummins (NTA 855 R4) diesel motors, each delivering up to of power to