Mekarski system

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Preserved Nantes compressed air tramcar at the AMTUIR museum
Mekarski tram in Paris during 1910 flooding, the top of the hot water tank and the regulator can be seen in front of the car; the 9 air tanks are below the tram.[1]

The Mekarski system was a compressed-air propulsion system for trams invented by Louis Mékarski or Louis Mékarsky (the correct spelling is uncertain) in the 1870s. He worked in France, was born in 1843 in Clermont-Ferrand (center of France) of Polish origin. Many references to him use the Polish name Ludwik Mękarski.


A problem with compressed-air propulsion is that the air cools as it expands, which can lead to the formation of ice in the power cylinders. Mekarski sought to overcome this problem by heating the air with steam, produced in a small boiler called a bouillotte.[2] It is uncertain whether the steam was mixed with the air, or whether there was a heat exchanger.

It was a single-stage engine in that air was expanded in one piston and then exhausted. The air was reheated after leaving the tank and before entering the engine. The reheater bubbled air through a hot water tank, picking up hot water vapor to improve the engine's range. An improved engine contained a high-pressure cylinder of 5​12 inches operating at 50-150 lb/ and a low-pressure cylinder of 8 inches, with an 8-inch piston stroke.[3]

The system was promoted as being suitable for use in congested streets and in tunnels, as compressed air produced no smoke or flames, and thus would not disturb horses or fill the carriage with soot and sparks like a steam engine.[4]

The system was tested in Paris in 1876 and introduced to the tramways of Nantes in 1879. It seems to have been a success at Nantes with a fleet of 94 trams in 1900. The Mekarski tramcars continued in use there until 1917, when they were replaced by electric trams.[5]

The system was used in England on the Wantage Tramway but did not find favour there because the compressor plant used more than four times as much coal as a steam locomotive. Between 1881 and 1883 an improved air car was used on the Caledonian Road tramway of the London Street Tramway Company.[6]


One Mekarski tramcar is preserved at Nantes.

See also[edit]


Wikisource-logo.svg "Popular Miscellany" in Popular Science Monthly Volume 19, July 1881

  • See external links
  1. ^ Mekarski compressed air trams – the principles
  2. ^ The MEKARSKI system
  3. ^ Air-Driven Tramcars, The Times, 22 July 1885
  4. ^ Prospectus, The Mékarski Compressed Air Traction Company (Limited), The Times, 26 February 1881
  5. ^ Mekarski – Nantes
  6. ^ Advertisement, The Improved Mékarski Compressed Air Engine Company, The Times, 20 June 1883

External links[edit]