The Prussian Class T 3 steam locomotives procured for the Prussian State Railways were 0-6-0 tank locomotives intended for local mixed traffic and shunting work. Together with the Prussian T 2, they were the first steam locomotives built according to the standard designs. The first units were delivered by Henschel in 1882, and the Prussian State Railway procured the class until 1910. Similar steam locomotives were also built for other customers, with the last one delivered in 1924. In total, more than 1,500 T 3 locomotives and identical locomotives were built. The main purchasers, besides the Prussian State Railway, were primarily small and industrial railways. In the 1920s, a large portion of the locomotives were retired by the newly founded Deutsche Reichsbahn; nevertheless, numerous locomotives remained in service long after the Second World War. The last locomotive – an industrial engine in Poland – was withdrawn in 1988. A total of 29 locomotives have been preserved.
Prussian T 3 locomotives and related types were among the most widely distributed, longest-serving, and most successful Prussian locomotives. The T 3 of the Prussian railways primarily included standardized locomotives of the III-4e design, but it also encompassed the less common III-4p design and several other locomotives. In practice, many identical or similar locomotives built for other regional, private, and industrial railways are associated with the class. Although these locomotives were not formally classified as part of the T3 series, they were similar in construction, and some later shared the fate of the machines of the class on other railways, including German railways as well as the Polish State Railways (PKP).
History The predecessors of this design were a class of five steam locomotives with a C axle arrangement, produced in 1881–1882 by Henschel in Cassel for the private Bergisch-Märkische Eisenbahn (BME). They featured a twin engine with a cylinder diameter of and a piston stroke of , as well as wheels with a diameter of . After the nationalization of the railways in 1882, they were taken over by the Prussian railways and later also classified as part of the T3 class. Most likely, the design, slightly modified, was subsequently selected by the Prussian standardization committee as a typical design for the Prussian railways.
Since 1882, Henschel and other German manufacturers began the production of a standardized type of tank locomotive with a C axle arrangement for the Prussian railways, designated as standardized model (Musterblatt) III-4e (originally, until 1883: M 12). They were equipped with a twin-cylinder engine with a cylinder diameter of and a piston stroke of , and initially wheels with a diameter of . After the introduction of the classification system for the Prussian railways in 1906, these locomotives were designated as T 3 (the letter T signified tank locomotives). In addition to 1302 locomotives of the III-4e type, the T3 group also included 52 reinforced locomotives of the III-4p type, produced between 1904 and 1906. In total, the Prussian railways received 1,354 standardized locomotives of the T3 group, produced up to 1906. Added to this were three locomotives acquired before 1910 from private railways.
Almost all renowned German locomotive manufacturers were involved in the production, numbering 19 of them:
Henschel & Son (385) Union Giesserei Königsberg (126) Hannoversche Maschinenbau AG (106) Schichau-Werke (105) Maschinenfabrik Christian Hagans (100) Hohenzollern Locomotive Works (93) Elsässische Maschinenbau-Gesellschaft Grafenstaden (93) Borsig Locomotive Works (76) Arnold Jung Lokomotivfabrik (73) Orenstein & Koppel (51) Maschinenbau Anstalt Humboldt (44) AG Vulcan Stettin (30) Schwartzkopff (30) Stahlbahnwerke Freudenstein (13) Linke-Hofmann-Werke AG (10) Maschinenbau-Gesellschaft Karlsruhe (10) Sächsische Maschinenfabrik (4) Maschinenfabrik Esslingen (4) Mecklenburgische Waggonfabrik-Aktiengesellschaft (1)
In this, 3 of the locomotive manufacturers were involved in production of the reinforced III-4p locomotives:
Maschinenfabrik Christian Hagans (25) Orenstein & Koppel (17) Stahlbahnwerke Freudenstein (10) Due to different manufacturers and a long production period, the locomotives differed from each other in details and characteristics, but within each of the two designs the differences were not significant. Early locomotives of the III-4e design did not have a steam dome, having only a throttle in a small casing on the boiler. However, soon, in the 1890s, in the second version locomotives, a sizable bell-shaped steam dome appeared on the boiler, and the wheel diameter was increased from 1080 to . Earlier locomotives were also modernized in this way. The first series had the rear wall of the cab cut obliquely at the bottom, whereas the others had a flat rear wall, and consequently were longer. Differences in weight did not exceed one ton. Greater differences appeared only in the reinforced locomotives of the III-4p model. The boiler parameters remained similar, and the engine cylinder dimensions were also retained, but their service weight increased from to , and the axle load increased from to , while the coal and water reserves were increased. All standardized locomotives had a characteristic uneven wheelbase: between the first and second axle and between the second and third axle. Another distinctive feature was the short coal bunkers on both sides of the boiler in front of the cab, as well as the internal water tank in the frame, which was connected by vertical pipes in front of the coal bunkers. In the III-4p model locomotives, the boiler was placed higher, but apart from the slightly longer coal bunkers (reaching the middle axle), they did not differ significantly externally from the later III-4e model locomotives.
In addition to 1,357 standardized locomotives of the III-4e and 4p models, 15 non-standardized locomotives were classified into the T3 group in Prussia, including five of the aforementioned earlier tank engines of the BME railway, as well as five early tank engines with the same axle arrangement produced by Henschel for the Main-Weser railway in 1881 (cylinder diameter , piston stroke , wheel diameter . Additionally, the T3 group included one of three locomotives built with a different B1 axle arrangement, model III-4g (Posen 6101) – bringing the total number of T3 group locomotives to 1,373.
Companies producing standardized III-4e type steam locomotives for the Prussian railways also built numerous locomotives of the same or a similar model for various private and industrial railways within the German Empire. Some differed in weight, engine cylinder dimensions, steam pressure, and boiler surface area, but they maintained the same design and characteristic asymmetric wheel spacing (1.7 / 1.3 m). Twenty locomotives were built for export to China, and another twenty to Italy, among which was the last locomotive constructed according to the III-4e design – in 1924 by Henschel for the Valtellina Railway.
Musterblatt III-4e design Tender locomotive with a C axle arrangement, equipped with a twin engine for saturated steam. Locomotives of different series and manufacturers varied in details and characteristics. Despite its small size, the boiler was very efficient and had a large firebox.J. Piwowoński: Parowozy..., p. 138, 179 The boiler barrel had a length of and accommodated 132 fire tubes. The boiler was positioned fairly low – the boiler axis in early locomotives was at a height of above the tracks, in later models – (due to an increase in wheel diameter by ), and in M III-4p locomotives at a height of . The grate had a surface area of 1.3 m², and in M III-4p locomotives – 1.35 m². The heating surface of the boiler typically measured 61.1 m², and in M III-4p locomotives – 61 m².
Initially, locomotives did not have a steam dome on the boiler, but only a throttle in a small housing, from which external pipes ran to the cylinders. Locomotives produced from the 1890s already had a fairly large cylindrical steam collector on the boiler, shifted further back. All series also had a small sandbox on the boiler. Most locomotives had a Latowski-type steam bell on the boiler (mounted in various locations). The first series had a rear wall of the cab that was cut obliquely at the bottom and a total length of , while the others had a vertical rear wall, and due to the extension of the frame at the rear (up to the rear wall), their length increased to , and in the III-4p model to . A characteristic feature of the appearance of locomotives of this type was the short coal boxes on both sides of the boiler in front of the cab, holding of coal ( in M III-4p locomotives), as well as the slanted side covers of the smokebox. The water tank was internal in the frame, with a capacity of 3.5–4 m³, into which water was poured through characteristic vertical pipes in front of the coal boxes, often funnel-shaped at the top. In III-4p type locomotives, the capacity was 5 m³.
The steam locomotives had a twin engine with a cylinder diameter of and a piston stroke of , with an Allan external valve gear. The wheel diameter was initially , and in the 1890s it was increased to . Initially, the locomotives had a hand brake, and later they were equipped with steam or pneumatic brakes. A Heberlein mechanical brake was used to brake the train.
The frame was made of plate steel, with a frame thickness of . The distance between the outer axles was 3 meters, with a distance of between the first and second axles and between the second and third axles. The axles were rigidly mounted, but the wheels of the driving axle (the second) had flanges reduced by , allowing the locomotive to negotiate curves with a radius of . The axle load was up to ( in the M III-4p type).
The Prussian T3 could pull freight trains loaded with a mass of at a speed of on a level track, and on a 20‰ incline, it could haul trains at a speed of .
Locomotives of similar types on other railways A total of more than 1,300 T 3s were built for the Prussian state railways. But many other railways in Germany and abroad, from industrial railways to national railways, also bought locomotives based on the T 3 pattern:
Grand Duchy of Mecklenburg Friedrich-Franz Railway Grand Duchy of Oldenburg State Railways Brunswick State Railway Kreis Oldenburger Railway Zschipkau-Finsterwald Railway Lower Lusatian Railway German Railway Operating Company Shantung railway (China) Chemins de fer Prince Henri (Luxembourg) Società Veneta (Italy) State Railway of Thailand (Thailand)
Mecklenburg Apart from Prussia, only two other German railway administrations used locomotives of a related type. The main user outside Prussia was Mecklenburg, whose Grand Duchy of Mecklenburg Friedrich-Franz Railway purchased 68 locomotives corresponding to the III-4e model between 1882 and 1906, built in 8 factories (Borsig, Güstrow, Hanomag, Henschel, Hohenzollern, Jung, Linke-Hofmann, and Schichau). The locomotives of the first series were designated as Mecklenburg type T3a and corresponded to the early Prussian locomotives with a cutout rear wall of the cab and a throttle without a steam collector, but with wheels of in diameter. The newer series of locomotives, built from 1900 onwards, were designated T3b. These railways were later taken over by the German Railways, and in 1925 there were still 40 locomotives in existence, which received new series numbers 8980 (89 8001 to 8022 and 89 8051 to 8068).
Oldenburg