Garratt was granted a patent for an innovative locomotive design in 1908, subsequently known as the "Garratt".
Beyer, Peacock & Company purchased sole rights of manufacture in Britain. After the patents ran out in 1928, the company began to use the name "Beyer-Garratt" to distinguish the locomotives they had manufactured. Garratt's design for an
articulated steam locomotive featured an engine unit at each end carrying coal and water supplies, and a boiler unit suspended between them on pivots. The design was deployed in many regions throughout Africa, South America, South-east Asia, Australia and New Zealand. In these regions, difficult terrain often prevailed, adding to construction costs. Usually the railway lines suffered from low load-bearing capacity because they had been built cheaply; Garratt locomotives, with their weight usually distributed over 12 to 16 driving wheels and 8 to 16 non-driving wheels, minimised destructive forces on rails. Additionally, because they were articulated, they could generally traverse sharper curves than non-articulated locomotives. Their higher ability to penetrate previously impassable regions often had the effect of increasing human and economic interactions between settlements, reducing the isolated nature of previously remote areas of the world. Garratt locomotives were particularly effective on
narrow gauge railway lines not only because of their flexibility: the size of their fireboxes below the "bridge" between the two engine units was constrained only by the lateral distance between the bridge frames – much greater than the distance between the narrow frames of non-articulated locomotives. This greatly increased the capacity to generate steam, on which power output depended. High efficiency compared with that of fixed-frame locomotives reduced the numbers of locomotives per train, allowed much heavier trains, and averted the need to convert rail lines to a wider gauge – an incentive for further rail network and economic expansion. ==Notes==