Bavarian S 2/5

The Class S 2/5 express locomotives of the Royal Bavarian State Railways (Königlich Bayerische Staats-Eisenbahnen) were the first steam engines in Germany to be built with full-length bar frames (durchgehendem Barrenrahmen). The prototypes for this type of frame were the two locomotives imported in 1900 from Baldwin Locomotive Works in the US, that had been similarly classified as the S 2/5.

Bavarian S 2/5
DRG Class 14.1
Bavarian S 2/5
Type and origin
BuilderMaffei
Build date1904
Total produced10
Specifications
Configuration:
​
 • Whyte4-4-2
 • GermanS 25.16
Gauge1,435 mm (4 ft 8+1⁄2 in)
Leading dia.950 mm (3 ft 1+3⁄8 in)
Driver dia.2,000 mm (6 ft 6+3⁄4 in)
Trailing dia.1,206 mm (3 ft 11+1⁄2 in)
Length:
​
 • Over beams19,275 mm (63 ft 2+3⁄4 in)
Axle load16.0 t (15.7 long tons; 17.6 short tons)
Adhesive weight32.0 t (31.5 long tons; 35.3 short tons)
Empty weight62.2 t (61.2 long tons; 68.6 short tons)
Service weight68.6 t (67.5 long tons; 75.6 short tons)
Tender typeBavarian 2′2′ T 21
Fuel capacity7 t (15,400 lb) of coal
Water cap.21.0 m3 (4,600 imp gal; 5,500 US gal)
Boiler:
​
No. of heating tubes278
Boiler pressure16 kgf/cm2 (1.57 MPa; 228 lbf/in2)
Heating surface:
 • Tubes		191 m2 (2,060 sq ft)
 • Firebox3.27 m2 (35.2 sq ft)
 • Radiative14.5 m2 (156 sq ft)
 • Evaporative205.50 m2 (2,212.0 sq ft)
Cylinders4, compound
Piston stroke640 mm (25+3⁄16 in)
High-pressure cylinder340 mm (13+3⁄8 in)
Low-pressure cylinder570 mm (22+7⁄16 in)
Valve gearWalschaerts (Heusinger)
Performance figures
Maximum speed110 km/h (68 mph)
Career
Numbers
  • K.Bay.Sts.E.: 3001–3010
  • DRG: 14 141 – 14 145
Retiredby 1927

History

In 1904, Maffei built ten engines that shared many of the same components as the S 3/5, which was developed in parallel. For example, they did not use a wider firebox, which would have been possible given the wheel arrangement, in order to be able to use one that could be used on the S 3/5. So the firebox was only around 90 mm wider than the bar frame of the locomotive. For manufacturing reasons the sole bar was still not made of one piece, but forged from several bars.

For the first time in Bavaria a driving wheel diameter of 2,000 mm was chosen instead of the 1,870 mm diameter hitherto the norm for express train locomotives. Like the locomotives imported from the United States, they had a four-cylinder compound engine. However the usual European (von Borries) configuration with two inside and two outside cylinders was used instead of the Vauclain compound system.

On test runs, one of the locomotives reached 135 km/h; in normal use, 110 km/h was the top speed. The locomotives were initially stabled at Munich I shed and hauled such famous trains as the Orient Express and the North-South Express, amongst others. But, as on all German Atlantics the traction of the two driven axles was soon insufficient. The S 2/5 was not blessed with a long time in service, although the locomotive had very good riding qualities and was seen as a genuinely fast runner.

In 1910 the locomotives went across to the Palatine network to Ludwigshafen shed and also to the Nuremberg repair shop. In 1922 only eight S 2/5 engines remained. The Deutsche Reichsbahn took over just five locomotives as the Class  14.1, numbered 14 141–145. They were retired in 1927.

The locomotives had Bavarian 2'2' T 21 tenders.

See also

References
    • Weisbrod, Manfred; Müller, Hans; Petznik, Wolfgang (1976). Dampflokomotiven deutscher Eisenbahnen, Baureihe 01–39 (EFA 1.1) (in German) (3rd ed.). Düsseldorf: Alba Buchverlag. pp. 97–98. ISBN 3-87094-081-6.
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