After his military service, he traveled to France in the autumn of 1893, and worked for the Fives-Lille Company as a junior engineer, where he designed and developed early induction motors for locomotives.

In 1907, the Italian government decided for the electrification of another 2000-km railway line with the restriction that the electrical equipment and rolling stock could only be manufactured in Italy.

On the District and Metropolitan Railways, the use of steam locomotives led to smoke-filled stations and carriages that were unpopular with passengers and by the early twentieth century electrification was seen as the way forward.

Initially, this was unanimously accepted by both parties,[16] until the district found an investor, the American Charles Yerkes, to finance the upgrade.

[21] The drive motors, made by Metropolitan-Vickers, had a very large diameter of 3 meters and incorporated four sets of 24 magnetic poles each, which could be added to the traction effort at will, producing highly efficient constant speeds of 25, 50, 75 and 100 km/h over rail (or 17/34/51/68 km/h for the V60 heavy freight train engine variant, which had six pairs of smaller driving wheels).

It had two independent windings: The MÁV company decided to electrify the 190 km long Budapest-Hegyeshalom main line with a new "Kandó system".

Based on experiences from the initial months, the prototype locomotive was redesigned under Kandó’s leadership in 1926: modifications were made to the phase converter, speed regulation system, and motor windings.

The 16 kV, single-phase current taken from the overhead line was directly supplied to the primary winding of the phase shifter through the pantograph and the main switch.

The phase shifter provided a constant 50-cycle current, so changing the speed and rotation was achieved by switching the motor's pole number.

A major benefit of this arrangement was a power factor of nearly 1.00 in the catenary-attached equipment, which fulfilled the electric powerplants' strict load-distributing regulations.

The unacceptably poor power factor of pre-World War II design electric motors (occasionally as low as 0.65) was not felt outside the Kando locomotives, as the phase changer machinery provided isolation.

Intermediate speeds were maintained by connecting a water and saltpeter based adjustable resistor to the line, which reduced the efficiency of the locomotive.

Timetables for electrified lines were supposed to allow use of full efficiency constant speeds most of the time but, in practice, the need to share the track with trains hauled by MÁV Class 424 steam locomotives meant the water-hungry and wasteful "gearbox resistor" had to be used often.

The propulsive force was transferred to the locomotive's wheels using a traditional pushrod system, designed to provide manufacturing and maintenance commodity to the predominantly steam-based Hungarian Railways (MÁV) of the time.

The so-called Kandó triangle arrangement[23] transferred power from the electric motor to the pushrods in such a way that no oblique forces were exerted on the chassis, making the V40 less hurtful to the rail track compared to steam engines.

Owing to Cold War restrictions, the innovative V55 type,[25] which used bogie-mounted motors, had to be constructed of domestic components entirely and suffered from reliability problems in their double-conversion phase-changer / frequency-changer propulsion system.

(The traction motors of pre-WWII V40 and V60 locomotives were made in Britain by the Metropolitan-Vickers company, as part of an economic aid programme organized by Lord Rothermere.)

They are preserved at the Budapest Railway History Park, but require restoration after decades of open air static display.

If funding permits, the repaired V40 may return to the open track for "nostalgic service", with a semiconductor front-end added to its system for 25 to 16 kV AC down-step conversion.

After his death, the development of the electric locomotive continued on the path he had set, under the direction of Ferenc Ratkovszky and Andor Mándi.

Many modern electric trains work on the same three-phase high tension AC principle introduced by the Kandó V40 locomotives, but the rotary converter is replaced by semiconductor devices.

More than 50 patents were bought by locomotive and rolling stock manufacturing companies in foreign countries like the UK, US, Germany, France and Italy.

In Miskolc, the square in front of the Tiszai railway station, where his statue is also standing, bears his name, as well as a vocational secondary school.

In Budapest, the Kandó Kálmán Faculty of Electrical Engineering (formerly an independent technical college, now part of Óbuda University), also bears his name.