between 1898–1902 (the last one served until 1958). was a (1B)B locomotive in service between 1905–1969 and until 1962. The strongest Mallet locomotives in Europe were the members of the MÁV 601 which was built for the Hungarian State Railways, it was a locomotive. With their 22.5 meter length, 163.3 tonnes total weight and 2200 KW power, the MÁV 601 was the biggest, the heaviest and most powerful steam locomotive built before and during the First World War in Europe. North American versions The first Mallet locomotive in the United States was Baltimore & Ohio Railroad number 2400, built by Alco in 1904. Nicknamed "Old Maude", it was a 0-6-6-0 weighing and with axle loads of . Received negatively at first due to speed limitation arising from the short wheelbase and stiff suspension, it gained support during service, and it was soon followed by Baldwin examples, and then steadily heavier and more powerful successors. In Canada, the Canadian Pacific Railway experimented with an unusual design of Mallet promoted by H.H. Vaughan, then Chief Mechanical Officer and Assistant to the CPR Vice-President. Their in-house compound 0-6-6-0 design located both the high and low pressure cylinders adjacent to one another in the center of the locomotive driving opposite directions. Produced in the CPR's Angus shops, road numbers 1950 to 1954 were outshopped between 1909 and 1911. An additional "simple" (as opposed to compound) unit with road #1955 featuring the same arrangement was also produced. These were used in helper service in the Rockies and Selkirks. The units were unpopular with crews owing to frequent steam leakages and derailments resulting from the lack of pilot wheels. While not an outright failure these were considered an unsuccessful design, and by 1916-1917 these units had been converted to a conventional 2-10-0 arrangement. These six locomotives were ultimately the only articulated locomotives operated by a Canadian railway. As weight and power and length increased, there were experiments with flexible boiler casings; from 1910 the Santa Fe road introduced jointed-boiler 2-6-6-2 locomotives weighing , with a long boiler barrel, with a firetube reheater and a firetube feedwater section in front, each separated by a blank section, and variants of a telescopic or bellows type boiler casing. These were unsuccessful, and later engines used conventional boilers. The largest compound Mallets were ten 2-10-10-2s built for the Virginian by Alco in 1918; in pairs they pushed coal trains headed