a curve and move to some extent laterally. Typically the support bearing was placed beneath the smokebox, hollowed and with a sliding seal to provide a route for exhaust steam from the low-pressure cylinders to discharge through a blastpipe within the smoke box. Mallet considered that the major advantage of this arrangement was that it enabled the cylinders on the truck to be fed with low-pressure steam: the high-pressure cylinders were on the fixed main frame and only low-pressure steam needed to be carried through movable pipes to the swivelling truck. The Mallet concept This then was what became understood as a "Mallet" locomotive: an articulated locomotive in which the rear set of driving wheels were fixed in the main frame of the locomotive; an articulated truck carrying a second set of driving wheels; and compounding in which the high-pressure cylinders drove the axles on the main frame and the articulated axles were driven by low-pressure steam. Mallet asserted that the advantages of his concept were: all the locomotive weight would be adhesive, yet there would be great flexibility of the locomotive as a vehicle; the difficulties with Meyer, Fairlie and other then-existing articulated systems would be eliminated as the moving pipes would be carrying low-pressure steam at only pressure, and would be easier to keep steam-tight; and A simple type of very powerful locomotive would be created. The large-diameter pipe conveying the low-pressure steam from the high-pressure to the low-pressure cylinders acted also as a receiver, forming a buffer for the gas flow. Independent cut-offs for the high-pressure and low-pressure cylinders were advocated by Mallet, but driving standards were inadequate and he later used combined cut-off control. European versions Large numbers of Mallet designs for narrow gauge railways were built, but in 1889 the first six standard gauge examples were built by J A Maffei for the Swiss Central railways, and an 87 tonne banker (US: pusher) for the Gotthard Bahn, the last being the most powerful and heaviest locomotive in the world at the time. By 1892 110 Mallets were at work, of which 24 were standard gauge; by 1900 there were nearly 400, of which 218 were on standard gauge or Russian gauge (). One of the examples in Germany was the class of s built by Maffei for Bavarian State Railways between 1913 and 1923. Mallet designs were popular in Hungary, too. 30 of were built