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NS 7100
N.F.L.S No. 1 in 1900.
Type and origin Power type Steam Builder Hohenzollern Build date Series 1: 1901-1902 Series 2: 1907-1908 Total produced 25
Specifications Configuration: ​  • Whyte 2-4-2  • UIC 1'B1' Gauge 1,435 mm (4 ft 8+1⁄2 in) Leading dia. Series 1: 1,000 mm (3 ft 3 in) Series 2: 1,100 mm (3 ft 7 in) Driver dia. Series 1: 1,520 mm (5 ft 0 in) Series 2: 1,540 mm (5 ft 1 in) Length Series 1: 10,220 mm (33 ft 6 in) Series 2: 10,473 mm (34 ft 4.3 in) Height 4,100 mm (13 ft 5 in) Loco weight Series 1: 43.2 t (47.6 short tons; 42.5 long tons) Series 2: 49 t (54 short tons; 48 long tons) Fuel type Coal Fuel capacity 2 t (2.2 short tons; 2.0 long tons) Water cap. Series 1: 4.5 m3 (990 imp gal) Series 2: 6 m3 (1,300 imp gal) Firebox: ​  • Grate area 1.42 m2 (15.3 sq ft) Boiler pressure Series 1: 12.4 kg/cm2 (176 psi) Series 2: 12 kg/cm2 (170 psi) Cylinders 2 Cylinder size 380 mm × 560 mm (15 in × 22 in) Valve gear Stephenson
Performance figures Maximum speed Series 1: 55 km/h (34 mph) later 80 km/h (50 mph) Series 2: 60 km/h (37 mph) later 80 km/h (50 mph) Tractive effort series 1: 4,620 kgf (10,200 lbf) series 2: 4,410 kgf (9,700 lbf)
Career Operators NS Numbers series 1: NFLS: 1-10, HSM: 1051-1060, NS: 7101-7110 series 2: SS: 531-545, NS: 7111-7125 Withdrawn series 1: 1925-1949 series 2: 1947-1948 Disposition All scrapped

The NS 7100 was a series of tank engines of the Dutch Railways (NS) and its predecessors Maatschappij tot Exploitatie van Staatsspoorwegen (SS), Hollandsche IJzeren Spoorweg-Maatschappij (HSM) and Noord-Friesche Locaalspoorweg-Maatschappij (NFLS).

At the beginning of the twentieth century, the NFLS ordered ten locomotives for local trains on the Leeuwarden - Stiens - Metslawier, Stiens - Harlingen, and Tzummarum - Franeker Halte lines from the Hohenzollern factory in Düsseldorf-Grafenberg. They were tank engines with the 1'B1' wheel arrangement, the leading axle of which was designed as an Adams axle. The first six locomotives entered service in 1901, followed by the other four in 1902. As of December 1, 1905, the operation of these lines was taken over by the HSM, whereby the locomotives and rolling stock was also taken over. The HSM renumbered the ten locomotives in the series 1051–1060.

When the locomotives and rolling stock fleet of the HSM and the SS was merged in 1921, the locomotives of this series were given the NS numbers 7101–7110. No. 7110 was withdrawn from service in 1925, followed by No. 7107 in 1939. At the end of World War II, Nos. 7104, 7105 and 7108 were taken to Germany, of which only No. 7108 was returned to service. Of the locomotives that remained in the Netherlands, Nos. 7102 and 7109 were not repaired from war damage. The locomotives that did return to service after the war were withdrawn in 1949.

A few years after the delivery of the first batch of ten tank locomotives, the SS ordered about fifteen similar locomotives from the same factory. The first seven were put into service in 1907 as SS 531–537. The SS 538-545 followed in 1908. The SS used these locomotives on light passenger trains on local railway lines. When the locomotives and rolling stock fleet of the HSM and the SS was merged in 1921, these locomotives were given the NS numbers 7111-7125 after the original ten HSM locomotives. No. 7114 was withdrawn from service in 1925, followed by No. 7116 in 1936.

During the German invasion, No. 7124 was run into the Potmarge near Leeuwarden to stop the advance of the enemy troops. After the locomotive was salvaged, it was not repaired. At the end of the war, Nos. 7117, 7118, 7120, 7122 and 7123 were taken to Germany. The first four returned damaged after the war, but were never repaired. No. 7123 did not return at all and was scrapped at Hagenow in 1951. Of the locomotives left behind in the Netherlands, Nos. 7113 and 7119 were not repaired from war damage. The remaining locomotives were withdrawn from service in 1947 and 1948.

• 
  The war damaged and withdrawn NS 7120 at Baarle Nassau Grens.
• 
  Some trains along the platform of Uithoorn station, with the NS 7116 on the right.
• 
  A locomotive of the series 7100 of the N.S. with a train between Hantum and Ternaard. (26-04-1935)
• 
  NS 7109 (NFLS No. 9) with a train along the platform of the Anjum station. (Between 1913 and 1920)
• 
  NS 7106 with a train along the platform of the Amsterdam Haarlemmermeer. (Between 1925 and 1935)
• 
  NS 7112 in Uithoorn (01-04-1940)
• 
  NS 7101 at Tjummarum station, with posing station staff. (1917 - 1922)
• 
  NS 7125 with the last passenger train on the route Tzummarum - Stiens. (14-05-1936)
• 
  NS 7103 in Susteren during electrification work. (14-05-1936)
• 
  NS 7103 during the electrification of the shunting yard in Susteren. (1948)
• 
  NS 7116 probably factory new. (1907)
• 
  A locomotive of the series NS 7100 with a train at Metslawier station. (1920 - 1940)

• H. Waldorp: Onze Nederlandse stoomlocomotieven in woord en beeld. Uitg. De Alk, Alkmaar, 1981. ISBN 90-6013-909-7.
• J.J. Karskens: De Locomotieven van de Hollandsche IJzeren Spoorweg Maatschappij. Uitg. J.H. Gottmer, Haarlem - Antwerpen, 1947.
• R.C. Statius Muller, A.J. Veenendaal jr., H. Waldorp: De Nederlandse stoomlocomotieven. Uitg. De Alk, Alkmaar, 2005. ISBN 90-6013-262-9
• Jacq. van der Meer: De Hollandsche IJzeren Spoorweg-Maatschappij. Uitg. Uquilair, Rosmalen, 2009. ISBN 90-71513-68-8.