Power for the electrification of railway traffic in Hungary could be extracted most economically from the nationwide 50 Hz electricity grid.

Therefore, Kálmán Kandó developed his eponymous drive system, which is based on single-phase AC overhead lines and three-phase traction motors.

The system was demonstrated on a test locomotive from 1923 and, from 1932 to 1935, the route from Budapest to Hegyeshalom was electrified at 16 kV, 50 Hz.

In the 1960s, the traction current system in Hungary was converted to 25 kV, 50 Hz and the Kandó locomotives were withdrawn.

Final drive was through a Kandó triangle with one arm connected to an auxiliary idling shaft to minimise unwanted vertical forces.