Short history of the MÁV Class V40 "Kandó" Electric Locomotives

Part 2

The Mainline Electrification and the Class V40 Loco

The Loco

The Line

The Opening and the First Experiences

In 1927 MÁV had the opportunity to get a large British loan to develop the railways, with emphasis on the electrification. Thus they decided to electrify the Budapest-Hegyeshalom mainline, 186km towards Vienna/Austria. One of the loan conditions was that a considerable part of the money should have been spent in Great Britain.

The Loco

Mr. Kandó designed a new boxcab-type phase converter locomotive, with 1-D-1 wheel arrangement. The phase converter - built by Ganz - was similar to the experimental one. In this case however he decided to use one single large (10') diameter traction motor, built by Metropolitan-Vickers in Manchester/Great Britain. This was a 48-pole asynchronous motor, with a rather unusual arrangement: the generating coils were on the rotor, while the shorting coils on the stator. The shorting coils were connected to a fluid resistor. This was a tank with large surface poles inside, and a small pump emptied the electrolyte into a higher located reservoir, when bigger resistance was needed. This was needed as the converter-motor unit had 4 synchronous speeds, at 25,50,75 and 100km/h (15.6, 31.2, 47 and 62.5 mph). Between these speeds the stator's shorting coil was shorted through the fluid resistor in order to avoid too strong acceleration and current overload. Thus the loco driver had to "switch the gears" when changing the speed.

kando loco roof with stack minipicThe fluid resistor's electrolyte was simple doped water. When after start high current flow through the fluid, the water warmed up, and the Kandó electric locos accelerated with large steam clouds above. They even had a short stack near the pantograph to exhaust steam.

kando loco rod drawing minipicThe motor drove the drivers using a slanted main rod. To maintain the vertical components of the forces an auxiliary (idling) shaft was inside the Kando loco drive minipiccab, that forwarded the forces from one side to the other one. The rods drove the connecting rods through the "Kandó-Triangle" that allowed only horizontal forces to the connecting rods. Two sets of pony wheels were located at each end of the loco. They were connected to the closest driver through a "Krauss-Helmholz" truck, that directed the first driver in the curve. This resulted a smooth run at speed.

The Line

The line was electrified with 16kV 50Hz. This voltage was probably chosen to be similar as the German and Austrian electrification voltage, thus their isolation standards and equipment could be used. The 186km line was divided into 3 sections with 3 different supply stations built by Metropolitan-Vickers. The stations contained simple transformers. At that time there was no country-wide electric system, thus it could happen that the phase was different in the different sections. The large gap between the loco's phase converter's rotor and stator allowed to cross phase boundaries without switching off the supply. There was a small kick, and the converter resynchronized itself immediately.

After trials Kandó developed a catenary suspension system with two rods and one wire, that can be seen today on most electric railways of the world. In lack of quality machines the whole catenary system was built using human power.

Kálmán Kandó did not live to see the opening of his life-work: he died January 13th 1931.

The Opening and the First Experiences

The first 90 km section of the line, from Budapest to Komárom was opened in September 1932. That time two mainline locos were available, thus the electric traction was rather an experimental one. The first passenger trains made big surprises for the conductors. At steam hauled trains they spent the time before starting by chatting with the engineer, and when the train started, they were waiting until the last car passed and jumped on it. This was impossible with the electric traction: the Kandó locomotives started so fast, that the conductors missed the trains.

MÁV V40 Kandó electric loco drive minipicSoon after the regular action started the main problem with the locos became visible: the rod-drive's key element, the Kandó triangle often broke. It was redesigned from higher quality materials, and the locomotives still under construction received this version. This problem, however, remained more-less serious for the whole lifetime of these engines.

Another interesting feature was the permanent usage of both pantographs. In order to avoid resynchronization caused by short time missing wire contact, always both pantographs were used on phase converter locos.

The Kandó-locos replaced all steamers in front of both passenger and freight trains. Their hauling capacity, 600ton train at 100kmph was almost double than those of the Class 301, four cylinder De-Glehn Pacific steamers, the pride of MÁV. As their traction force was almost as high as the those of the heaviest coal train hauling steamers, one considered the even higher traction capability of the freight version, V60 as unnecessary. V40s hauled freight trains too, except the heaviest coal trains between Tatabánya and Budapest.

The full Hungarian section of the Budapest-Vienna line was electrified in October 1934. The financial analysis proved that the electrification was a full success. Soon 25 pieces of  V40 and 3 pieces of V60 engines were in revenue service, and MÁV made big plans for a country-wide electrification.


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This page was updated last time on 30th August 2000
© János Erö