Anatole Mallet

Jules T. Anatole Mallet ( * May 23, 1837 in Lancy ( Canton of Geneva ), † 10 October 1919 ) was a Swiss engineer and his time one of the most successful designers of steam locomotives.

Training

Mallet studied and taught at the Ecole Centrale des Arts et Manufactures and began with the construction and planning of port facilities, including the Suez Canal later.

Steam engines

In 1867, he first worked with the construction of steam engines and developed the idea of the composite machine. He tried also applicable to steam locomotives of this principle. In the same year, and in close connection with the first patent patenting an starting device, which made it possible to introduce steam into the low-pressure cylinder of the compound steam engine, hence speeding up the starting process of a locomotive was.

Caused a stir Mallet 1876, when he presented two tank locomotives on the railroad Bayonne -Biarritz with a two-cylinder compound engine in service. In principle, the locomotives were working, however, had at higher speeds rough running due to the not fully balanced performance differences of the high pressure and low pressure cylinder. Mallet could not at the time convinced of the composite principle, the railway companies. Even after the development of improved designs with pairwise built-in high - and low-pressure cylinders, the complexity of the machines seemed rather daunting to the majority of the railway companies. The later developed steam superheating proved to be more successful way to energy efficiency compared to the composite principle.

The development of Malletlok

Increased traffic on narrow-gauge railways opened up Mallet another field of activity. These tracks needed stronger and thus larger machines as it would allow the tight curves of the narrow-gauge lines. The only solution seemed to be locomotives with pivoting bogies here. For this purpose, the types of Fairlie and Meyer were already widespread, used swiveling machine units. The individual units were supplied with steam via flexible connections, but always proved to be a weak point of the machine. Mallet instead developed a design with two carriages, of which the front, located under the smoke chamber suspension was pivoted only while the boiler rested firmly on the other chassis. Thus the number of flexible compounds was reduced by half.

However, the essential difference of the construction of Mallet compared to the types and Fairlie Meyer was the perfect application of a composite engine. The steam is first fed to the high-pressure cylinders of the fixed -bearing chassis, and after the outlet of the low pressure cylinder of the movable front chassis. The there leading portable steam line connection was better controlled than with pure steam supply due to the lower pressure. This design allowed Mallet patented in 1884. The first built in this way Malletlokomotive was introduced in 1888 in Belgium for Paul Decauville 600 mm narrow gauge railway at the Paris Exhibition in 1889 and carried there over six million visitors. Later, more successful with this principle, narrow gauge locomotives were built, mostly with the BB wheel arrangement, ie with two each two-axle engines.

1904, the Baltimore & Ohio Railroad, the Mallet concept in the United States with the order of a C'C - Loktype with the American Locomotive Company in. In 1911, the U.S. had more than 500 mallets. During the First World War, the Virginian Railway drove the original Mallet concept to the extreme with the order of machines, the wheel arrangement ( 1'E ) 'E1', whose low-pressure cylinder had a diameter of 48 inches (120 cm). Thus also the limits of the Mallet- concept were visible. The overhang of the boiler and the low-pressure cylinders were so great that it was hardly possible to develop suitable valves for them. They could only be operated at low speeds. In later, larger locomotives that were still called mallets, was waived to the composite principle of separate landing gear and supplies both tracks with live steam. Further improvements have been made in order to achieve higher speed with the machine to standard gauge tracks. The Mallet design brought in the United States produced the largest ever built steam locomotives.

Anatole Mallet himself no longer took part in the further improvement as he pursued his principle priority for use of the composite machine. To 1888, he designed still has the original locomotives for the Lartigue Monorail. In the 20th century Mallet was regarded as the " Grand Old Man" of the French engineers, who wrote occasional essays on locomotives for the annals of the French society of civil engineers. Little is known about the people Mallet beyond its success as a mechanical engineer, although he is considered one of the three major locomotive engineers after the era of Stephenson.

In Germany you can find today the Mallet type steam locomotives still on the tracks of the Harz narrow gauge railway in daily use at scheduled times.