Bavarian S 3/5

The Class S 3/5 engines of the Royal Bavarian State Railways (Königlich Bayerische Staatsbahn) were express train steam locomotives with a 4-6-0 wheel arrangement.

Bavarian S 3/5 N DRG Class 17.4
Bavarian S 3/5 Nr. 3303
Number(s)	K.Bay.Sts.E.: 3301–3328, 3330–3340 DRG 17 401 – 17 420 CF Est 3351–3363 AL 982–986
Quantity	39
Manufacturer	Maffei
Year(s) of manufacture	1903–1907
Retired	1928ff.
Wheel arrangement	4-6-0
Axle arrangement	2′C n4v
Track gauge	1,435 mm (4 ft 8 ^1⁄2 in)
Length over buffers	19,325 mm (63 ft 4 ^3⁄4 in)
Service weight	69.8 t (68.7 long tons; 76.9 short tons)
Adhesive weight	45.0 t (44.3 long tons; 49.6 short tons)
Axle load	15.0 t (14.8 long tons; 16.5 short tons)
Top speed	110 km/h (68 mph)
Indicated Power	1,100 PS (809 kW; 1,080 hp)
Driving wheel diameter	1,870 mm (6 ft 1 ^5⁄8 in)
Leading wheel diameter	950 mm (3 ft 1 ^3⁄8 in)
No. of cylinders	4, compound
LP cylinder bore	570 mm (22 ^7⁄16 in)
HP cylinder bore	1st series: 335 mm (13 ^3⁄16 in) 2nd/3rd series: 340 mm (13 ^3⁄8 in)
Piston stroke	640 mm (25 ^3⁄16 in)
Boiler Overpressure	1st series: 14 kgf/cm^2 (1.37 MPa; 199 psi) 2nd/3rd series: 16 kgf/cm^2 (1.57 MPa; 228 psi)
Grate area	3.27 m^2 (35.2 sq ft)
Evaporative heating area	164.43 m^2 (1,769.9 sq ft)
Tender	bay 2′2′ T 21/21.8
Water capacity	21.0 or 21.8 m^3 (4,600 or 4,800 imp gal; 5,500 or 5,800 US gal)

Saturated steam variant

Between 1903 and 1907 Maffei delivered three batches of 39 locomotives in all. They had a four-cylinder, saturated steam compound engine. Unlike their forerunners, the Bavarian Class C V, the inside high-pressure cylinders and the outside low-pressure cylinders were angled and worked on the first coupled axle.

From the second series, built in 1904, the boiler pressure of the S 3/5 was raised from 14 to 16 bar (1,400 to 1,600 kPa; 200 to 230 psi). The tube lengths and diameter of the inside cylinders were also changed.

The S 3/5 engines built from 1904 were technically closely related to the S 2/5 which was being developed in parallel. The two classes only differed in their wheel arrangement and the larger coupled wheel diameter on the S 2/5; the boiler and running gear were the same and thus also their output power. Even the permitted top speed was identical on both classes (110 km/h or 68 mph). The S 3/5 N engines were, in terms of tractive effort (300 tonnes or 295 long tons or 331 short tons at 100 km/h or 62 mph), clearly superior to the S 2/5, because they had three driven axles. S 3/5 locomotives were stabled in the locomotive workshops at Munich I and Nuremberg.

The locomotives were coupled with Bavarian 2'2' T 21 and 2'2' T 21,8 tenders.

Superheated steam variant

Bavarian S 3/5 H DRG Class 17.5
Number(s)	K.Bay.Sts.E.: 3329, 3341–3369 DRG: 17 501 – 17 524
Quantity	30
Manufacturer	Maffei
Year(s) of manufacture	1906–1911
Retired	by 1948
Wheel arrangement	4-6-0
Axle arrangement	2′C h4v
Service weight	71.9 t (70.8 long tons; 79.3 short tons)
Adhesive weight	48.0 t (47.2 long tons; 52.9 short tons)
Axle load	16.0 t (15.7 long tons; 17.6 short tons)
Indicated Power	1,260 PS (927 kW; 1,240 hp)
LP cylinder bore	590 mm (23 ^1⁄4 in)
HP cylinder bore	360 mm (14 ^3⁄16 in)
Superheater area	33.90 m^2 (364.9 sq ft)
data shown where different

For the 1906 Bavarian State Exhibition in Nuremberg, Maffei fitted locomotive no. 3329 experimentally with a Schmidt superheater. In addition the bore of the cylinders was increased to 360 mm (14.173 in)/590 mm (23.228 in). These measures produced a significant improvement in locomotive performance (450 tonnes or 440 long tons or 500 short tons on the level at 100 km/h or 62 mph), so that from 1908 the Bavarian state railways only ordered the superheated S 3/5 H.

Although the more powerful S 3/6 express locomotive had been available since 1908, the number of S 3/5 H engines had climbed to 30 by 1911, partly because there was insufficient funding for the expensive S 3/6. As a result, the overall number of S 3/5 engines was 69.

Reichsbahn

After World War I, 19 saturated steam and 6 superheated steam locomotives had to be transferred abroad. Seventeen of those went to the French Eastern Railway, five to the AL and two to the Belgian state railway. Locomotive no. 3333 was left in Poland after the war and was numbered by the PKP as Ok 103-1.

The Deutsche Reichsbahn took over the remaining 20 saturate steam engines as Class 17.4 (17 401–420) and had them converted to superheated locomotives in 1925. The remaining 24 superheated engines became Class 17.5 (17 501–524). In the meantime the S 3/5 was mainly used on passenger train duties in the Reichsbahndirektionen of Augsburg and Nuremberg, because enough modern express engines were now available.

The Reichsbahn began to retire the locomotives as early as 1932. Initially the older, former saturated steam engines disappeared, only eight examples remaining after the Second World War; whilst at the same time 21 of the former S 3/5 H locomotives were still working. All the engines were in Bavaria by the end of the war, but were heavily worn out and no longer ran in regular service. Both variants were finally retired by 1948.

See also

• Royal Bavarian State Railways
• List of Bavarian locomotives and railbuses

Sources

• Weisbrod; Müller, Manfred; Petznick, Wolfgang (1976). Dampflokomotiven Deutscher Eisenbahnen Baureihe 01-39. Düsseldorf: Alba. ISBN 3-87094-081-6.
• von Welser, Ludwig; Huschläger, Helge (2001). Bayern-Report. Band No. 9. Fürstenfeldbrück: Merker. ISBN 3-89610-081-5.