Mallet (locomotive)
The Mallet (pronounced: Malleh) type is a special type of steam locomotive with a two-part engine for winding mountain routes. It was developed in 1884 by the Swiss engineer Anatole Mallet . With the principle of split engines, mallet locomotives of the Günther-Meyer type are similar , but in contrast to these they only have one bogie (see schematic diagram).
Mallet type
The Mallet type has two independent trolleys. The rear undercarriage is connected to the frame in the normal way. The front running gear with its own frame and piston steam engine, on the other hand, is movably connected to the main frame of the locomotive via a pivot .
Another characteristic of the Mallet design is the way the steam engine works with a compound effect , with the high-pressure cylinders acting on the rear group of engines. This meant that no moving high-pressure steam lines were required. Compound locomotives with high-pressure and low-pressure cylinders acting on different groups of engines, however, have a great tendency towards alternating skidding of both engines. Another fundamental disadvantage of the Mallet composite locomotives was their inadequate suitability for higher speeds. With the introduction of superheated steam , it therefore made sense to forego the composite effect.
Mallet locomotives are or were used both on mountain and narrow-gauge railroads and on mainline railways in heavy freight train service. In the USA in particular , the largest steam locomotives ever built emerged and became very popular as articulated locomotives .
In November 1913, the Royal Bavarian State Railways put a first Gt 2 × 4/4 on the tracks for the pushing service on the Hochstadt-Marktzeuln – Probstzella railway line . Between April and July 1914, the Rothenkirchen locomotive station at the southern foot of the Frankenwald ramp received ten locomotives of this series, and another five came to Aschaffenburg for use on the Spessart ramp . In 1922/23 ten more machines were procured. When the 96 011 was shut down in March 1947, the locomotives, now run as the 96 series, came to an end in West Germany . In the GDR , the last copy was taken out of service by the Deutsche Reichsbahn in 1954 after years of storage.
Triplex design
In an extension of the “mallet principle”, the American Baldwin Locomotive Works built four so-called triplex locomotives from 1914 to 1916 . The Erie Railroad procured three triplex vehicles with the axle formula (1'D) D + D1 '. The Virginian Railway Triplex class XA had the axle formula (1'D) D + D2 '.
These triplex locomotives were mallets that had an additional drive set with two low-pressure cylinders under the tender . With these machines , however, the evaporation capacity of the large boiler was problematic. Since the exhaust steam from the drive unit was conducted under the tender via a second chimney on the tender, it was available for preheating the boiler feed water, but not for venting the boiler using the blowpipe . In addition, the pulling power of this triplex, which was built to pull trains with 64 wagons of 50 t each, was so great that the frames of the wagons and the couplings broke. They were probably the most powerful steam locomotives ever built, but could only generate their pulling power at very low speeds without suffering from a lack of steam. Triplex locomotives were therefore not a success, so that they were taken out of service again after a short time.
Similar locomotives
The American series 4000 ("Big Boy") of the Union Pacific Railroad (UP), an articulated locomotive with the wheel arrangement (2'D) D2 'h4, is one of the largest and most powerful steam locomotive series in the world. In contrast to the mallet machines, however, these are not compound locomotives, as they worked with simple steam expansion without compound action. In America, this design is called "Simple articulated".
At the same time as Mallet, but independently of him, the German Fritz Rimrott developed a similar principle, in which, however, the movable engine group was at the rear. Rimrott locomotives were never built, but the Mallet-Rimrott designation persisted in Germany for a long time.
Operational mallet locomotives
Germany
In Germany , operational mallet locomotives are still on the meter-gauge Harz narrow-gauge railways . The Frankfurter Feldbahnmuseum also has an operational field railroad mallet locomotive for a gauge of 600 mm. Since May 1, 2015, the 11sm locomotive on the Brohltalbahn has been in regular operation again (after around 50 years of inactivity). The well from the opening credits of the TV show Eisenbahn-Romantik known Württemberg Tssd 99633 is in Oechsle train between Warthausen and Ochsenhausen in Upper Swabia in use.
In general inspection (for a restart) is a machine of the Museum Railway Bruchhausen-Vilsen - Asendorf ( German Railway Club ).
As the last representative of its kind, Germany's only standard gauge Mallet locomotive of the type Bayerische BB II formerly Deutsche Reichsbahn (1920-1945) number 98 727 is being refurbished in the Darmstadt-Kranichstein Railway Museum.
Switzerland
In Switzerland , ready-to-use Mallet locomotives (as of 2010) are on the meter-gauge Blonay-Chamby (BC) museum railway in western Switzerland (SEG G 2x2 / 2 105) and at SBB under the care of SBB Historic ( SCB Ed 2x2 / 2 196 , Standard gauge ).
France
Two meter-gauge mallet locomotives are in use on the Train de l'Ardèche museum railway in the French Ardèche department from mid-March to mid-November. Locomotive 403 with the CC wheel arrangement (French: 030-030-T) was built by the Swiss locomotive and machine factory SLM Winterthur and delivered in 1903. Locomotive 414 from 1932, also a 030-030-T, comes from the SACM in Graffenstaden in Alsace .
Narrow gauge locomotive 99 5906 of the Harz Narrow Gauge Railways
Narrow gauge locomotive 11sm of the Brohltalbahn
Swiss Ed 2 × 2/2 196
Mallet locomotive No. 403 of the Train de l'Ardèche
Mallet locomotive No. 414 of the Train de l'Ardèche
Web links
- The 11sm narrow-gauge mallet steam locomotive of the Brohl Valley Railway is put back into operation
- Private website about mallet locomotives
Individual evidence
- ^ Konrad Koschinski: Mallet giants for the ramps . In: Frankenwaldbahn . Railway Journal special, No. 1 , 2018, p. 38 ff .
- ^ Raimar Lehmann: Steam locomotive special designs . Springer, ISBN 978-3-0348-6757-3 , pp. 42 .