Prussian State 4-6-0 Locomotives in Germany

Class P7 (Locobase 6458)

Data from Christian Lindecke's German locomotive website [] (29 Jan 2005) and from "4-Cylinder Compound Locomotive, Prussian State Rys" The Locomotive Magazine, Vol IX (14 November 1903), p. 284

Gustav Reder (1974, p 214) says this is one of the few examples of a de Glehn compound design to run in Prussia and the only Ten-wheeler.

According to the Polish locomotive website, the P7 was an adaptation of the Baden State Railway's Class IV. The LM report notes that the class were "...practically duplicates of the 3.121-3.225 class of France's Nord Railway [Locobase 3890], except they are provided with the Prussian pattern of cab, safety valves, firebox, injectors, and sandbox."

The P7 was not well received on the KPEV, hence the early decision to limit production to 18 locomotives.

Class P8 / 1908 (Locobase 8959)

Data from Albert H Bone, "Some Recent Designs of Locomotives for Service on Continental Railways", Cassier's Magazine, 1910, pp. 561-609.

As noted in Locobase 1269, the P8 was "a huge class that saw a few changes over its long production life." This later entry probably represents the class as it went into service. Note the larger cylinders and boiler and the smaller amount of superheat; the firebox was probably the least-altered component in the design.

Bone notes that this design came from the well-known Herr Prive Councillor Garbe of the KPEV with detail design and construction by the BMAG. Bone comments that they were "...[b]uilt especially for heavy and rapid haulage on difficult lines ..." and having lived up to expectations, they were "...well spoken of by their drivers as being powerful and elastic machines, capable of tackling big loads under adverse conditions of rails and weather." A trial run hauling 56 axles and 464 tons behind the tender averaged 60 km/h (37.3 mph) over 123 miles of "...heavily graded road, with five booked stops ..."

Class P8 / BR 38 10-38 40 (Locobase 1269)

Data from Polish museum website [], AE A[nthony] E[dward] Durrant, The steam loc, Christian Lindecke's [] (2 May 2004), and the US Military Railway Service's Equipment Data Book (supplied in March 2004 by Allen Stanley). See also See also Gustav Reder (Michael Reynolds, trans), The world of steam locomotives (New York: Putnam, 1974); and the Linke-Hoffmann variant with Lentz poppet valves at SMU's DeGolyer Library special collections website, [], last accessed 23 October 2013.

(See Locobase 8959 for the design as it entered service.)

A huge class that saw a few changes over its long production life. Cylinder diameter was reduced at least twice, superheater surface increased by 108 sq ft,(10.03 sq m) and the valve motion received the Kuhn sliding loop to smooth it out. The railroad's tonnage ratings for this class were 700 tons at 50 mph (81 km/h) on the flat, 300 tons at 31 mph (50 km/h) up a 1% grade.

"Simple, economical and hard-working," wrote Gustav Reder, noting that it was so well-suited to passenger and express service where high speed wasn't necessary that several thousand went to the KPEV alone. By the end of World War I, 2,350 of these engines had entered servicce. After the Armistice, reparation settlements sent 628 of these to other countries including 168 to Belgium as Class 64, 162 to France (later classed 230C & 230F),

Germany then built replacements to bring the total to 3,438 Another 500 were built in other countries; for example see Locobase 5298 for details on Romania's program. According to Reder, the number of locomotives purchased "has never been exceeded by any other type of passenger locomotive."

Marklin's site ([] erh/eurorailhobbies.asp?PageID=437 ) provides a handy checklist and diagram of notable features. Among those highlighted were:

The American design archbar trucks, which reduced the tare weight of the tender;

A barrel-shaped cab roof extending well back over the deck to the tender, keeping the fireman dry in bad weather.

The locomotive plate frame consisted of 25 mm (1") thick sheet metal that prevented one from seeing through the underside of the locomotive.

The three sets of driving wheels were rigidly mounted in the frame. Equalizers connected the two rear sets and improved the smoothness during operation.

Also typical is the cast iron valve gear bracket with two oval openings.

The large diameter of the smoke box set it off from the boiler.

The Witte smoke deflectors give the locomotive engineer a clear view.

This truck with its inboard frame could swing to both sides by 40 mm (1-9/16") and was spring loaded to return to the center position.

Class S 8/S 10/ BR 17.0-17.1 (Locobase 1264)

Data from US Military Railway Service Equipment Data Book -- German Locomotives supplied from the extensive collection of Allen Stanley (March 2004). See also Albert Gieseler's Dampflokomotiven website at [], last accessed 10 November 2015.

This four-cylinder express locomotive entered service to provide more power and adhesion for the longer and heavier trains then being assembled. Christian Lindecke ([], visited 29 Dec 2003) says that after Schwartzkopff's S 10 appeared at the Brussels Exposition, engineers and mechanics found that the inside cylinders were difficult to get at and work on.

The simple-expansion layout's difficulties inspired two kinds of modification. One led to the S 10.1 series of four-cylinder compounds described in Locobases 5800 and 1265. The other kept the single-expansion, but eliminated one of the two inside cylinders; see Locobase 1266.

The DRG assigned class numbers to 135 locomotives -- BR 17 001-135, but the four-cylinder layout required frequent maintenance and the S 10s were retired by the mid-1930s.

This diagram book gives 1,067 sq ft for the superheater surface, which is much higher than either Lindecke or [] . It isn't a conversion issue, it seems, because the guide's other values are very precise.

Class S10.1 - Henschel (Locobase 5800)

Data from "New express locomotives of the Prussian State Railway", translated from the Rivista tecnica dello ferrovie italiene/Italian Railway Technical Journal and found in Monthly Bulletin (English Version), International Railway Congress Association (P Wessenbruch, 1912), pp. 821-825. See also "Compound Superheater Express Locomotive, Royal Prussian State Railways", Locomotive Magazine, Volume 18 (14 December 1911), p. 252; and Albert Gieseler's Dampflokomitven entry at [], last accessed 11 September 2016. (Thanks to Claus Gaertner for his 17 March 2021 email providing the proper transliteration of the builder's name.)

Once the demerits of the Henschel four-cylinder simple-expansion S8 (later S10) were registered during initial testing, the company turned to a four-cylinder compound design by Bavarian native Georg Heise, says Johannes Wittmann as part of an email debate over the merits of simple vs compounding ([] ). Wittmann notes "...the preference for compounds is not part of the genetic material of Bavarians..A four-cylinder compound may be a good choice for a fast express train loco, or a huge freight engine, but for a common working horse?"

According to the Rivista Tecnica, the advantages of four-cylinder compounding included the absence of superheated steam being exhausted to the environment (a wasteful result of simple-expansion superheating) and a compensation for some leakage through the high-pressure piston valves "because any eventual losses in the high-pressure valves are recovered in the low-pressure cylinders, or because any eventual losses in the low-pressure valves are naturally of less importance.".

(Both arguments seem a little weak to Locobase. Steam locomotives were extravagantly wasteful of heat energy in general--the goal was to get as much power to the drivers as possible. Recovering steam leakage in the low-pressure cylinders seems wishful and discounting leakage in low-pressure steam valves diminishes the double-expansion value of compounding.)

Joost Wilbrink ([]) gives us some details about the S10. In its Henschel-built prototype form, the inside valve motions were too inaccessible and the boiler pressure too low.

Class S10.1 / BR 17.11- 17.12 (Locobase 1265)

Data from US Military Railway Service Equipment Data Book -- German Locomotives supplied from the extensive collection of Allen Stanley (March 2004). See also Albert Gieseler's Dampfmaschinen und Lokomotiven website at [], last accessed 11 November 2015.

When Henschel introduced its compound version (Locobase 5800) of the original S8/S10 four-cylinder simple-expansion Ten-wheeler express engine (Locobase 1264) , the company addressed the designs's high fuel consumption and maintenance complications. But its energy-generating system was too small and operated at too low a boiler pressure.

The 1914 engines shown here reflected the KPEV's service experience and introduced changes. Boiler pressure rose by a bar (14.5 psi), grate, firebox, evaporative heating surface, and superheating surface areas all increased for a relatively modest increase in weight. Also, the steam path between the HP cylinders driving the first axle and the LP cylinders turning the second set proved too long..The new design put all four cylinders on a slant and relocated them to shorten the distance.

The outside cylinders rode higher on the boiler and had a more substantial appearance that, together with raising the running board, The result looked like the most powerful express engine on the Prussian railways and performance matched the look.

Class S10.2 / BR 17.2 (Locobase 1266)

Data from Albert Gieseler's Dampfmaschinen und Lokomotiven website at [], last accessed 11 November 2015. See also [] and

the US Military Railway Service Equipment Data Book for German Locomotives supplied by Allen Stanley from his extensive Rail Data Exchange in March 2004.

All three cylinders of this simple-expansion Ten-wheeler drove on the same axle.

Joost Wilbrink ([] - June 2002) noted that the DRG took in 96 of this class and used several in experiments with high-pressure boilers.17.206 received a 60-bar (853-psi) boiler produced by Schmidtschen Hei+dampfgesellschaft and later superheated steam at 14 bar (ca. 200 psi) to 440 deg C.

Later experiments with "medium-pressure" boilers delivered good results, but the wear and tear forced a reduction to 16 bar. Ultimately, non of the experiments resulted in an improvement sufficient to outweigh the complexity, cost, and coal consumption.

Of the original batch of Vulkans, 88 survived the six years of World War Two, but were retired by 1948.

Class T10 / 76.0 (Locobase 6040)

Christian Lindecke ([], 29 December 2003) for data. Additional data from US Military Railway Service Equipment Data Book -- German Locomotives supplied from the extensive collection of Allen Stanley (March 2004) and from Albert H Bone, "Some Recent Designs of Locomotives for Service on Continental Railways", Cassier's Magazine, 1910, pp. 561-609; "Preuáische T 10" in Wikipedia at [], last accessed 21 October 2022; "2C gekuppelte Heissdampf-Schnellzug-Tenderlokomotive mit Schmidts Rauchrohrenuberhitzer, der preussischen Staatseiesenbahnen", Die Lokomotive, Year 6, Issue 6 (June 1909), pp. 126-128 in the Oersterreich Nationalbibliothek at []; and Albert Gieseler's Dampmaschinen und Lokomitven website at [], last accessed 14 October 2018. Works numbers were 6941-6945 in 1909, 7288 in 1910, and 8151-8156 in 1912.

These Ten-wheeler tanks were build to pull express trains over the 26 miles (42 km) between Frankfurt-am-Main and Wiesbaden. Wikipedia describes Prussian State's Robert Garbe's 1908 analysis of three options. He preferred a superheated 4-6-0 (2'C h2) locomotive rolling on 1,650 mm (65") drivers over a similar design with 1,750 mm drivers. His rejection of the alternative reflected the design's required overlong 3,100 mm (10 ft 2 in) connecting rods. The third design also would be superheated, but use a 4/4/2 (1'B2') wheel arrangement.

In the event, the railway adopted the 1,750 mm design as shown in the specs, but built only a dozen locomotives. They proved to be fast (100 kph/62 mph), steady running forward, but betraying a tendency to derail when backing up. Fuel and water only allowed 3 runs (120 km/74.5 miles) which meant the T10s couldn't work a full commuting day.