A Garratt system steam locomotive is a type of articulated steam locomotive in which steam engines are located on two separate crews that house water and fuel tanks. On these two crews, a bridge frame is installed on which the steam boiler is located. This system was first proposed by the English engineer Garratt ( Eng. Herbert William Garratt, 1864-1913 ), in whose honor it got its name. The advantage of such a system is that on a steam locomotive it is possible to obtain a grate of greater width, and therefore area. The disadvantage of this system was the large fluctuation in the grip weight at the consumption of water and fuel, as well as the long steam lines from the boiler to the machines, which led to large losses of heat and steam condensation at low temperatures.
Locomotives of such a system were most widely used on narrow gauge railways in Africa and Australia , where, with limited dimensions, this system made it possible to obtain a larger firebox, which made it possible to increase the capacity of the locomotive. Also, several steam locomotives of this system were operated on the railways of South America .
In the USSR, the only model of the Garratt system was an experimental steam locomotive of type 2-4-1-1-4-4 of the Ya-01 series. It was made in 1932 in England and in the same year entered the NKPS railways. However, the use of such a locomotive on Soviet railways did not meet the expectations of specialists - the use of the system did not give a significant increase in the capacity of the locomotive. Therefore, after the tests, the engine was soon removed from the train service, and in 1957 it was cut into scrap metal.
A locomotive of the Garatt system can be seen in the Vilanova Railway Museum ( Vilanova i la Geltru municipality in the province of Barcelona , Spain ).