NS 3900

Nederlandse Spoorwegen

Industry	Railway transport
Founded	1929
Headquarters	Netherlands
Products	Express steam locomotives (NS 3900 series)

Steam locomotive NS 3922; circa 1930. Collection of the Utrecht Archives.

The NS 3900 series comprised express steam locomotives operated by the Nederlandse Spoorwegen (Dutch Railways). Notably, the NS 3900 represented the final express steam engine specifically engineered for use within the Netherlands. Although the NS 4000 series was procured during wartime from Sweden, that class was derived from an existing Swedish design rather than a Dutch original.

History

In the late 1920s, Dutch Railways required a more powerful express locomotive than the existing 3700 series to accommodate the increasing replacement of wooden passenger cars with heavier steel coaches. This transition allowed the axle load to be raised from approximately . The resulting design incorporated elements from both the NS 3600 and NS 3700 classes, maintaining a 2'C wheel arrangement. The NS 3900 employed the bar frame similar to the NS 3600 but featured boiler, cylinder, and cab designs reminiscent of the NS 3700, albeit enhanced with a larger boiler and cylinders measuring in diameter instead of the previous . This increase led to roughly a 15% boost in tractive effort. The boiler design was subsequently reused on the tank locomotives of the 6300 series. Its tender resembled that of both the NS 3600 and later eight-wheeled tenders from the NS 3700 series. The NS 3900 was capable of rapidly accelerating even the heaviest passenger trains to speeds of up to 100 km/h (62 mph).

Manufactured by Henschel & Sohn in two production runs during 1929 and 1930, the initial batch consisted of twenty-two units (numbers 3901–3922) produced without smoke deflectors, which were added in 1930. The second batch of ten locomotives (numbers 3923–3932) came equipped with smoke deflectors upon delivery.

These locomotives hauled the heaviest express and D trains until electrification began; however, they faced certain drawbacks. Neither the NS 3900 nor its related class, the NS 6300, could be operated by hand firing effectively, and their rated power output of approximately was attainable only when using high-quality coal and experienced firemen. Technically, they were considered flawed: their boiler design was outdated, as were their cylinders and valve systems. Additionally, construction quality issues led to cracked inner fireboxes and uneven wear on various sliding bearings within the cylinder blocks.

Soon after entering service, concerns regarding their reliability emerged. These issues were corroborated by observations that similar problems did not affect the related NS 6300 series except for higher coal consumption. Following investigations by multiple committees, modifications were implemented that largely alleviated many faults; nonetheless, persistent steaming inefficiencies remained throughout their operational life despite numerous trials. The cylinder block construction complicated extensive repairs since major alterations often required complete replacement—a costly measure ultimately not undertaken for this series.

When diesel three-car trainsets introduced on central routes encountered difficulties delivering fast service between major cities, they were supplemented by so-called steam diesel services—short express trains pulled by steam locomotives capable of maintaining diesel multiple unit schedules. Trial runs involving locomotives from series 2100, 3700, and 3900 revealed that both the former two outperformed the NS 3900 in speed. This discrepancy was attributed to higher rolling resistance inherent to the NS 3900 design, making it less suited for lightweight express duties.

Following World War II and rapid electrification of primary lines, utilization of the NS 3900 diminished progressively, relegated mainly to express or D trains on routes awaiting electrification completion. None of these locomotives have been preserved; however, boiler number from unit NS 3927 is retained within preserved locomotive NS 6317.

Gallery

• 
  NS 3911 at Nunspeet station; approximately 1930. From the Utrecht Archives collection.
• 
  NS 3911 positioned at Rotterdam Delftsche Poort station; around 1930. Source: Utrecht Archives.
• 
  A steam locomotive belonging to the 3900 series stationed at Amsterdam Central; year 1932.
• 
  The cab of NS 3902 showcased during the "100 years of railways in the Netherlands" exhibition held at Frederiksplein, Amsterdam (September 1939).
• 
  An NS 3900 unit hauling a coal freight near Wijchen on March 25, 1953.
• 
  Replica of the N.S. steam engine "De Arend" displayed alongside a series 3900 steam locomotive at Zwolle’s central workshop.
• 
  NS 3904 undergoing maintenance at the Central Workshop in Tilburg, with NS 3601 visible on the right (June 30, 1933).
• 
  NS 3916 pulling steel coaches close to Baarn.
• 
  Image of NS 3931.
• 
  Interior view of the driver's cabin from a NS series 3900 steam locomotive.

Sources

• Martin van Oostrom: Stoomlocomotieven serie NS 6300, published by Stichting Railpublicaties Rosmalen, 1985. ISBN 90-71513-01-7.